Java tutorial
/* * Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.lang; import java.lang.annotation.Annotation; import java.lang.constant.ClassDesc; import java.lang.invoke.TypeDescriptor; import java.lang.module.ModuleReader; import java.lang.ref.SoftReference; import java.io.IOException; import java.io.InputStream; import java.io.ObjectStreamField; import java.lang.reflect.AnnotatedElement; import java.lang.reflect.AnnotatedType; import java.lang.reflect.Array; import java.lang.reflect.Constructor; import java.lang.reflect.Executable; import java.lang.reflect.Field; import java.lang.reflect.GenericArrayType; import java.lang.reflect.GenericDeclaration; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Member; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import java.lang.reflect.Proxy; import java.lang.reflect.Type; import java.lang.reflect.TypeVariable; import java.lang.constant.Constable; import java.net.URL; import java.security.AccessController; import java.security.PrivilegedAction; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.HashMap; import java.util.LinkedHashMap; import java.util.LinkedHashSet; import java.util.List; import java.util.Map; import java.util.Objects; import java.util.Optional; import java.util.StringJoiner; import java.util.stream.Stream; import java.util.stream.Collectors; import jdk.internal.HotSpotIntrinsicCandidate; import jdk.internal.loader.BootLoader; import jdk.internal.loader.BuiltinClassLoader; import jdk.internal.misc.Unsafe; import jdk.internal.module.Resources; import jdk.internal.reflect.CallerSensitive; import jdk.internal.reflect.ConstantPool; import jdk.internal.reflect.Reflection; import jdk.internal.reflect.ReflectionFactory; import jdk.internal.vm.annotation.ForceInline; import sun.invoke.util.Wrapper; import sun.reflect.generics.factory.CoreReflectionFactory; import sun.reflect.generics.factory.GenericsFactory; import sun.reflect.generics.repository.ClassRepository; import sun.reflect.generics.repository.MethodRepository; import sun.reflect.generics.repository.ConstructorRepository; import sun.reflect.generics.scope.ClassScope; import sun.security.util.SecurityConstants; import sun.reflect.annotation.*; import sun.reflect.misc.ReflectUtil; /** * Instances of the class {@code Class} represent classes and interfaces * in a running Java application. An enum type is a kind of class and an * annotation type is a kind of interface. Every array also * belongs to a class that is reflected as a {@code Class} object * that is shared by all arrays with the same element type and number * of dimensions. The primitive Java types ({@code boolean}, * {@code byte}, {@code char}, {@code short}, * {@code int}, {@code long}, {@code float}, and * {@code double}), and the keyword {@code void} are also * represented as {@code Class} objects. * * <p> {@code Class} has no public constructor. Instead a {@code Class} * object is constructed automatically by the Java Virtual Machine * when a class loader invokes one of the * {@link ClassLoader#defineClass(String,byte[], int,int) defineClass} methods * and passes the bytes of a {@code class} file. * * <p> The methods of class {@code Class} expose many characteristics of a * class or interface. Most characteristics are derived from the {@code class} * file that the class loader passed to the Java Virtual Machine. A few * characteristics are determined by the class loading environment at run time, * such as the module returned by {@link #getModule() getModule()}. * * <p> Some methods of class {@code Class} expose whether the declaration of * a class or interface in Java source code was <em>enclosed</em> within * another declaration. Other methods describe how a class or interface * is situated in a <em>nest</em>. A <a id="nest">nest</a> is a set of * classes and interfaces, in the same run-time package, that * allow mutual access to their {@code private} members. * The classes and interfaces are known as <em>nestmates</em>. * One nestmate acts as the * <em>nest host</em>, and enumerates the other nestmates which * belong to the nest; each of them in turn records it as the nest host. * The classes and interfaces which belong to a nest, including its host, are * determined when * {@code class} files are generated, for example, a Java compiler * will typically record a top-level class as the host of a nest where the * other members are the classes and interfaces whose declarations are * enclosed within the top-level class declaration. * * <p> The following example uses a {@code Class} object to print the * class name of an object: * * <blockquote><pre> * void printClassName(Object obj) { * System.out.println("The class of " + obj + * " is " + obj.getClass().getName()); * } * </pre></blockquote> * * <p> It is also possible to get the {@code Class} object for a named * type (or for void) using a class literal. See Section 15.8.2 of * <cite>The Java™ Language Specification</cite>. * For example: * * <blockquote> * {@code System.out.println("The name of class Foo is: "+Foo.class.getName());} * </blockquote> * * @param <T> the type of the class modeled by this {@code Class} * object. For example, the type of {@code String.class} is {@code * Class<String>}. Use {@code Class<?>} if the class being modeled is * unknown. * * @author unascribed * @see java.lang.ClassLoader#defineClass(byte[], int, int) * @since 1.0 */ public final class Class<T> implements java.io.Serializable, GenericDeclaration, Type, AnnotatedElement, TypeDescriptor.OfField<Class<?>>, Constable { private static final int ANNOTATION = 0x00002000; private static final int ENUM = 0x00004000; private static final int SYNTHETIC = 0x00001000; private static native void registerNatives(); static { registerNatives(); } /* * Private constructor. Only the Java Virtual Machine creates Class objects. * This constructor is not used and prevents the default constructor being * generated. */ private Class(ClassLoader loader, Class<?> arrayComponentType) { // Initialize final field for classLoader. The initialization value of non-null // prevents future JIT optimizations from assuming this final field is null. classLoader = loader; componentType = arrayComponentType; } /** * Converts the object to a string. The string representation is the * string "class" or "interface", followed by a space, and then by the * fully qualified name of the class in the format returned by * {@code getName}. If this {@code Class} object represents a * primitive type, this method returns the name of the primitive type. If * this {@code Class} object represents void this method returns * "void". If this {@code Class} object represents an array type, * this method returns "class " followed by {@code getName}. * * @return a string representation of this class object. */ public String toString() { return (isInterface() ? "interface " : (isPrimitive() ? "" : "class ")) + getName(); } /** * Returns a string describing this {@code Class}, including * information about modifiers and type parameters. * * The string is formatted as a list of type modifiers, if any, * followed by the kind of type (empty string for primitive types * and {@code class}, {@code enum}, {@code interface}, or * <code>@</code>{@code interface}, as appropriate), followed * by the type's name, followed by an angle-bracketed * comma-separated list of the type's type parameters, if any, * including informative bounds on the type parameters, if any. * * A space is used to separate modifiers from one another and to * separate any modifiers from the kind of type. The modifiers * occur in canonical order. If there are no type parameters, the * type parameter list is elided. * * For an array type, the string starts with the type name, * followed by an angle-bracketed comma-separated list of the * type's type parameters, if any, followed by a sequence of * {@code []} characters, one set of brackets per dimension of * the array. * * <p>Note that since information about the runtime representation * of a type is being generated, modifiers not present on the * originating source code or illegal on the originating source * code may be present. * * @return a string describing this {@code Class}, including * information about modifiers and type parameters * * @since 1.8 */ public String toGenericString() { if (isPrimitive()) { return toString(); } else { StringBuilder sb = new StringBuilder(); Class<?> component = this; int arrayDepth = 0; if (isArray()) { do { arrayDepth++; component = component.getComponentType(); } while (component.isArray()); sb.append(component.getName()); } else { // Class modifiers are a superset of interface modifiers int modifiers = getModifiers() & Modifier.classModifiers(); if (modifiers != 0) { sb.append(Modifier.toString(modifiers)); sb.append(' '); } if (isAnnotation()) { sb.append('@'); } if (isInterface()) { // Note: all annotation types are interfaces sb.append("interface"); } else { if (isEnum()) sb.append("enum"); else sb.append("class"); } sb.append(' '); sb.append(getName()); } TypeVariable<?>[] typeparms = component.getTypeParameters(); if (typeparms.length > 0) { sb.append(Arrays.stream(typeparms).map(Class::typeVarBounds) .collect(Collectors.joining(",", "<", ">"))); } if (arrayDepth > 0) sb.append("[]".repeat(arrayDepth)); return sb.toString(); } } static String typeVarBounds(TypeVariable<?> typeVar) { Type[] bounds = typeVar.getBounds(); if (bounds.length == 1 && bounds[0].equals(Object.class)) { return typeVar.getName(); } else { return typeVar.getName() + " extends " + Arrays.stream(bounds).map(Type::getTypeName).collect(Collectors.joining(" & ")); } } /** * Returns the {@code Class} object associated with the class or * interface with the given string name. Invoking this method is * equivalent to: * * <blockquote> * {@code Class.forName(className, true, currentLoader)} * </blockquote> * * where {@code currentLoader} denotes the defining class loader of * the current class. * * <p> For example, the following code fragment returns the * runtime {@code Class} descriptor for the class named * {@code java.lang.Thread}: * * <blockquote> * {@code Class t = Class.forName("java.lang.Thread")} * </blockquote> * <p> * A call to {@code forName("X")} causes the class named * {@code X} to be initialized. * * @param className the fully qualified name of the desired class. * @return the {@code Class} object for the class with the * specified name. * @exception LinkageError if the linkage fails * @exception ExceptionInInitializerError if the initialization provoked * by this method fails * @exception ClassNotFoundException if the class cannot be located */ @CallerSensitive public static Class<?> forName(String className) throws ClassNotFoundException { Class<?> caller = Reflection.getCallerClass(); return forName0(className, true, ClassLoader.getClassLoader(caller), caller); } /** * Returns the {@code Class} object associated with the class or * interface with the given string name, using the given class loader. * Given the fully qualified name for a class or interface (in the same * format returned by {@code getName}) this method attempts to * locate, load, and link the class or interface. The specified class * loader is used to load the class or interface. If the parameter * {@code loader} is null, the class is loaded through the bootstrap * class loader. The class is initialized only if the * {@code initialize} parameter is {@code true} and if it has * not been initialized earlier. * * <p> If {@code name} denotes a primitive type or void, an attempt * will be made to locate a user-defined class in the unnamed package whose * name is {@code name}. Therefore, this method cannot be used to * obtain any of the {@code Class} objects representing primitive * types or void. * * <p> If {@code name} denotes an array class, the component type of * the array class is loaded but not initialized. * * <p> For example, in an instance method the expression: * * <blockquote> * {@code Class.forName("Foo")} * </blockquote> * * is equivalent to: * * <blockquote> * {@code Class.forName("Foo", true, this.getClass().getClassLoader())} * </blockquote> * * Note that this method throws errors related to loading, linking or * initializing as specified in Sections 12.2, 12.3 and 12.4 of <em>The * Java Language Specification</em>. * Note that this method does not check whether the requested class * is accessible to its caller. * * @param name fully qualified name of the desired class * @param initialize if {@code true} the class will be initialized. * See Section 12.4 of <em>The Java Language Specification</em>. * @param loader class loader from which the class must be loaded * @return class object representing the desired class * * @exception LinkageError if the linkage fails * @exception ExceptionInInitializerError if the initialization provoked * by this method fails * @exception ClassNotFoundException if the class cannot be located by * the specified class loader * @exception SecurityException * if a security manager is present, and the {@code loader} is * {@code null}, and the caller's class loader is not * {@code null}, and the caller does not have the * {@link RuntimePermission}{@code ("getClassLoader")} * * @see java.lang.Class#forName(String) * @see java.lang.ClassLoader * @since 1.2 */ @CallerSensitive public static Class<?> forName(String name, boolean initialize, ClassLoader loader) throws ClassNotFoundException { Class<?> caller = null; SecurityManager sm = System.getSecurityManager(); if (sm != null) { // Reflective call to get caller class is only needed if a security manager // is present. Avoid the overhead of making this call otherwise. caller = Reflection.getCallerClass(); if (loader == null) { ClassLoader ccl = ClassLoader.getClassLoader(caller); if (ccl != null) { sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); } } } return forName0(name, initialize, loader, caller); } /** Called after security check for system loader access checks have been made. */ private static native Class<?> forName0(String name, boolean initialize, ClassLoader loader, Class<?> caller) throws ClassNotFoundException; /** * Returns the {@code Class} with the given <a href="ClassLoader.html#binary-name"> * binary name</a> in the given module. * * <p> This method attempts to locate, load, and link the class or interface. * It does not run the class initializer. If the class is not found, this * method returns {@code null}. </p> * * <p> If the class loader of the given module defines other modules and * the given name is a class defined in a different module, this method * returns {@code null} after the class is loaded. </p> * * <p> This method does not check whether the requested class is * accessible to its caller. </p> * * @apiNote * This method returns {@code null} on failure rather than * throwing a {@link ClassNotFoundException}, as is done by * the {@link #forName(String, boolean, ClassLoader)} method. * The security check is a stack-based permission check if the caller * loads a class in another module. * * @param module A module * @param name The <a href="ClassLoader.html#binary-name">binary name</a> * of the class * @return {@code Class} object of the given name defined in the given module; * {@code null} if not found. * * @throws NullPointerException if the given module or name is {@code null} * * @throws LinkageError if the linkage fails * * @throws SecurityException * <ul> * <li> if the caller is not the specified module and * {@code RuntimePermission("getClassLoader")} permission is denied; or</li> * <li> access to the module content is denied. For example, * permission check will be performed when a class loader calls * {@link ModuleReader#open(String)} to read the bytes of a class file * in a module.</li> * </ul> * * @since 9 * @spec JPMS */ @CallerSensitive public static Class<?> forName(Module module, String name) { Objects.requireNonNull(module); Objects.requireNonNull(name); ClassLoader cl; SecurityManager sm = System.getSecurityManager(); if (sm != null) { Class<?> caller = Reflection.getCallerClass(); if (caller != null && caller.getModule() != module) { // if caller is null, Class.forName is the last java frame on the stack. // java.base has all permissions sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION); } PrivilegedAction<ClassLoader> pa = module::getClassLoader; cl = AccessController.doPrivileged(pa); } else { cl = module.getClassLoader(); } if (cl != null) { return cl.loadClass(module, name); } else { return BootLoader.loadClass(module, name); } } /** * Creates a new instance of the class represented by this {@code Class} * object. The class is instantiated as if by a {@code new} * expression with an empty argument list. The class is initialized if it * has not already been initialized. * * @deprecated This method propagates any exception thrown by the * nullary constructor, including a checked exception. Use of * this method effectively bypasses the compile-time exception * checking that would otherwise be performed by the compiler. * The {@link * java.lang.reflect.Constructor#newInstance(java.lang.Object...) * Constructor.newInstance} method avoids this problem by wrapping * any exception thrown by the constructor in a (checked) {@link * java.lang.reflect.InvocationTargetException}. * * <p>The call * * <pre>{@code * clazz.newInstance() * }</pre> * * can be replaced by * * <pre>{@code * clazz.getDeclaredConstructor().newInstance() * }</pre> * * The latter sequence of calls is inferred to be able to throw * the additional exception types {@link * InvocationTargetException} and {@link * NoSuchMethodException}. Both of these exception types are * subclasses of {@link ReflectiveOperationException}. * * @return a newly allocated instance of the class represented by this * object. * @throws IllegalAccessException if the class or its nullary * constructor is not accessible. * @throws InstantiationException * if this {@code Class} represents an abstract class, * an interface, an array class, a primitive type, or void; * or if the class has no nullary constructor; * or if the instantiation fails for some other reason. * @throws ExceptionInInitializerError if the initialization * provoked by this method fails. * @throws SecurityException * If a security manager, <i>s</i>, is present and * the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class. */ @CallerSensitive @Deprecated(since = "9") public T newInstance() throws InstantiationException, IllegalAccessException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), false); } // Constructor lookup Constructor<T> tmpConstructor = cachedConstructor; if (tmpConstructor == null) { if (this == Class.class) { throw new IllegalAccessException("Can not call newInstance() on the Class for java.lang.Class"); } try { Class<?>[] empty = {}; final Constructor<T> c = getReflectionFactory() .copyConstructor(getConstructor0(empty, Member.DECLARED)); // Disable accessibility checks on the constructor // access check is done with the true caller java.security.AccessController.doPrivileged(new java.security.PrivilegedAction<>() { public Void run() { c.setAccessible(true); return null; } }); cachedConstructor = tmpConstructor = c; } catch (NoSuchMethodException e) { throw (InstantiationException) new InstantiationException(getName()).initCause(e); } } try { Class<?> caller = Reflection.getCallerClass(); return getReflectionFactory().newInstance(tmpConstructor, null, caller); } catch (InvocationTargetException e) { Unsafe.getUnsafe().throwException(e.getTargetException()); // Not reached return null; } } private transient volatile Constructor<T> cachedConstructor; /** * Determines if the specified {@code Object} is assignment-compatible * with the object represented by this {@code Class}. This method is * the dynamic equivalent of the Java language {@code instanceof} * operator. The method returns {@code true} if the specified * {@code Object} argument is non-null and can be cast to the * reference type represented by this {@code Class} object without * raising a {@code ClassCastException.} It returns {@code false} * otherwise. * * <p> Specifically, if this {@code Class} object represents a * declared class, this method returns {@code true} if the specified * {@code Object} argument is an instance of the represented class (or * of any of its subclasses); it returns {@code false} otherwise. If * this {@code Class} object represents an array class, this method * returns {@code true} if the specified {@code Object} argument * can be converted to an object of the array class by an identity * conversion or by a widening reference conversion; it returns * {@code false} otherwise. If this {@code Class} object * represents an interface, this method returns {@code true} if the * class or any superclass of the specified {@code Object} argument * implements this interface; it returns {@code false} otherwise. If * this {@code Class} object represents a primitive type, this method * returns {@code false}. * * @param obj the object to check * @return true if {@code obj} is an instance of this class * * @since 1.1 */ @HotSpotIntrinsicCandidate public native boolean isInstance(Object obj); /** * Determines if the class or interface represented by this * {@code Class} object is either the same as, or is a superclass or * superinterface of, the class or interface represented by the specified * {@code Class} parameter. It returns {@code true} if so; * otherwise it returns {@code false}. If this {@code Class} * object represents a primitive type, this method returns * {@code true} if the specified {@code Class} parameter is * exactly this {@code Class} object; otherwise it returns * {@code false}. * * <p> Specifically, this method tests whether the type represented by the * specified {@code Class} parameter can be converted to the type * represented by this {@code Class} object via an identity conversion * or via a widening reference conversion. See <em>The Java Language * Specification</em>, sections 5.1.1 and 5.1.4 , for details. * * @param cls the {@code Class} object to be checked * @return the {@code boolean} value indicating whether objects of the * type {@code cls} can be assigned to objects of this class * @exception NullPointerException if the specified Class parameter is * null. * @since 1.1 */ @HotSpotIntrinsicCandidate public native boolean isAssignableFrom(Class<?> cls); /** * Determines if the specified {@code Class} object represents an * interface type. * * @return {@code true} if this object represents an interface; * {@code false} otherwise. */ @HotSpotIntrinsicCandidate public native boolean isInterface(); /** * Determines if this {@code Class} object represents an array class. * * @return {@code true} if this object represents an array class; * {@code false} otherwise. * @since 1.1 */ @HotSpotIntrinsicCandidate public native boolean isArray(); /** * Determines if the specified {@code Class} object represents a * primitive type. * * <p> There are nine predefined {@code Class} objects to represent * the eight primitive types and void. These are created by the Java * Virtual Machine, and have the same names as the primitive types that * they represent, namely {@code boolean}, {@code byte}, * {@code char}, {@code short}, {@code int}, * {@code long}, {@code float}, and {@code double}. * * <p> These objects may only be accessed via the following public static * final variables, and are the only {@code Class} objects for which * this method returns {@code true}. * * @return true if and only if this class represents a primitive type * * @see java.lang.Boolean#TYPE * @see java.lang.Character#TYPE * @see java.lang.Byte#TYPE * @see java.lang.Short#TYPE * @see java.lang.Integer#TYPE * @see java.lang.Long#TYPE * @see java.lang.Float#TYPE * @see java.lang.Double#TYPE * @see java.lang.Void#TYPE * @since 1.1 */ @HotSpotIntrinsicCandidate public native boolean isPrimitive(); /** * Returns true if this {@code Class} object represents an annotation * type. Note that if this method returns true, {@link #isInterface()} * would also return true, as all annotation types are also interfaces. * * @return {@code true} if this class object represents an annotation * type; {@code false} otherwise * @since 1.5 */ public boolean isAnnotation() { return (getModifiers() & ANNOTATION) != 0; } /** * Returns {@code true} if this class is a synthetic class; * returns {@code false} otherwise. * @return {@code true} if and only if this class is a synthetic class as * defined by the Java Language Specification. * @jls 13.1 The Form of a Binary * @since 1.5 */ public boolean isSynthetic() { return (getModifiers() & SYNTHETIC) != 0; } /** * Returns the name of the entity (class, interface, array class, * primitive type, or void) represented by this {@code Class} object, * as a {@code String}. * * <p> If this class object represents a reference type that is not an * array type then the binary name of the class is returned, as specified * by * <cite>The Java™ Language Specification</cite>. * * <p> If this class object represents a primitive type or void, then the * name returned is a {@code String} equal to the Java language * keyword corresponding to the primitive type or void. * * <p> If this class object represents a class of arrays, then the internal * form of the name consists of the name of the element type preceded by * one or more '{@code [}' characters representing the depth of the array * nesting. The encoding of element type names is as follows: * * <blockquote><table class="striped"> * <caption style="display:none">Element types and encodings</caption> * <thead> * <tr><th scope="col"> Element Type <th scope="col"> Encoding * </thead> * <tbody style="text-align:left"> * <tr><th scope="row"> boolean <td style="text-align:center"> Z * <tr><th scope="row"> byte <td style="text-align:center"> B * <tr><th scope="row"> char <td style="text-align:center"> C * <tr><th scope="row"> class or interface * <td style="text-align:center"> L<i>classname</i>; * <tr><th scope="row"> double <td style="text-align:center"> D * <tr><th scope="row"> float <td style="text-align:center"> F * <tr><th scope="row"> int <td style="text-align:center"> I * <tr><th scope="row"> long <td style="text-align:center"> J * <tr><th scope="row"> short <td style="text-align:center"> S * </tbody> * </table></blockquote> * * <p> The class or interface name <i>classname</i> is the binary name of * the class specified above. * * <p> Examples: * <blockquote><pre> * String.class.getName() * returns "java.lang.String" * byte.class.getName() * returns "byte" * (new Object[3]).getClass().getName() * returns "[Ljava.lang.Object;" * (new int[3][4][5][6][7][8][9]).getClass().getName() * returns "[[[[[[[I" * </pre></blockquote> * * @return the name of the class or interface * represented by this object. */ public String getName() { String name = this.name; return name != null ? name : initClassName(); } // Cache the name to reduce the number of calls into the VM. // This field would be set by VM itself during initClassName call. private transient String name; private native String initClassName(); /** * Returns the class loader for the class. Some implementations may use * null to represent the bootstrap class loader. This method will return * null in such implementations if this class was loaded by the bootstrap * class loader. * * <p>If this object * represents a primitive type or void, null is returned. * * @return the class loader that loaded the class or interface * represented by this object. * @throws SecurityException * if a security manager is present, and the caller's class loader * is not {@code null} and is not the same as or an ancestor of the * class loader for the class whose class loader is requested, * and the caller does not have the * {@link RuntimePermission}{@code ("getClassLoader")} * @see java.lang.ClassLoader * @see SecurityManager#checkPermission * @see java.lang.RuntimePermission */ @CallerSensitive @ForceInline // to ensure Reflection.getCallerClass optimization public ClassLoader getClassLoader() { ClassLoader cl = getClassLoader0(); if (cl == null) return null; SecurityManager sm = System.getSecurityManager(); if (sm != null) { ClassLoader.checkClassLoaderPermission(cl, Reflection.getCallerClass()); } return cl; } // Package-private to allow ClassLoader access ClassLoader getClassLoader0() { return classLoader; } /** * Returns the module that this class or interface is a member of. * * If this class represents an array type then this method returns the * {@code Module} for the element type. If this class represents a * primitive type or void, then the {@code Module} object for the * {@code java.base} module is returned. * * If this class is in an unnamed module then the {@linkplain * ClassLoader#getUnnamedModule() unnamed} {@code Module} of the class * loader for this class is returned. * * @return the module that this class or interface is a member of * * @since 9 * @spec JPMS */ public Module getModule() { return module; } // set by VM private transient Module module; // Initialized in JVM not by private constructor // This field is filtered from reflection access, i.e. getDeclaredField // will throw NoSuchFieldException private final ClassLoader classLoader; /** * Returns an array of {@code TypeVariable} objects that represent the * type variables declared by the generic declaration represented by this * {@code GenericDeclaration} object, in declaration order. Returns an * array of length 0 if the underlying generic declaration declares no type * variables. * * @return an array of {@code TypeVariable} objects that represent * the type variables declared by this generic declaration * @throws java.lang.reflect.GenericSignatureFormatError if the generic * signature of this generic declaration does not conform to * the format specified in * <cite>The Java™ Virtual Machine Specification</cite> * @since 1.5 */ @SuppressWarnings("unchecked") public TypeVariable<Class<T>>[] getTypeParameters() { ClassRepository info = getGenericInfo(); if (info != null) return (TypeVariable<Class<T>>[]) info.getTypeParameters(); else return (TypeVariable<Class<T>>[]) new TypeVariable<?>[0]; } /** * Returns the {@code Class} representing the direct superclass of the * entity (class, interface, primitive type or void) represented by * this {@code Class}. If this {@code Class} represents either the * {@code Object} class, an interface, a primitive type, or void, then * null is returned. If this object represents an array class then the * {@code Class} object representing the {@code Object} class is * returned. * * @return the direct superclass of the class represented by this object */ @HotSpotIntrinsicCandidate public native Class<? super T> getSuperclass(); /** * Returns the {@code Type} representing the direct superclass of * the entity (class, interface, primitive type or void) represented by * this {@code Class}. * * <p>If the superclass is a parameterized type, the {@code Type} * object returned must accurately reflect the actual type * arguments used in the source code. The parameterized type * representing the superclass is created if it had not been * created before. See the declaration of {@link * java.lang.reflect.ParameterizedType ParameterizedType} for the * semantics of the creation process for parameterized types. If * this {@code Class} represents either the {@code Object} * class, an interface, a primitive type, or void, then null is * returned. If this object represents an array class then the * {@code Class} object representing the {@code Object} class is * returned. * * @throws java.lang.reflect.GenericSignatureFormatError if the generic * class signature does not conform to the format specified in * <cite>The Java™ Virtual Machine Specification</cite> * @throws TypeNotPresentException if the generic superclass * refers to a non-existent type declaration * @throws java.lang.reflect.MalformedParameterizedTypeException if the * generic superclass refers to a parameterized type that cannot be * instantiated for any reason * @return the direct superclass of the class represented by this object * @since 1.5 */ public Type getGenericSuperclass() { ClassRepository info = getGenericInfo(); if (info == null) { return getSuperclass(); } // Historical irregularity: // Generic signature marks interfaces with superclass = Object // but this API returns null for interfaces if (isInterface()) { return null; } return info.getSuperclass(); } /** * Gets the package of this class. * * <p>If this class represents an array type, a primitive type or void, * this method returns {@code null}. * * @return the package of this class. * @revised 9 * @spec JPMS */ public Package getPackage() { if (isPrimitive() || isArray()) { return null; } ClassLoader cl = getClassLoader0(); return cl != null ? cl.definePackage(this) : BootLoader.definePackage(this); } /** * Returns the fully qualified package name. * * <p> If this class is a top level class, then this method returns the fully * qualified name of the package that the class is a member of, or the * empty string if the class is in an unnamed package. * * <p> If this class is a member class, then this method is equivalent to * invoking {@code getPackageName()} on the {@linkplain #getEnclosingClass * enclosing class}. * * <p> If this class is a {@linkplain #isLocalClass local class} or an {@linkplain * #isAnonymousClass() anonymous class}, then this method is equivalent to * invoking {@code getPackageName()} on the {@linkplain #getDeclaringClass * declaring class} of the {@linkplain #getEnclosingMethod enclosing method} or * {@linkplain #getEnclosingConstructor enclosing constructor}. * * <p> If this class represents an array type then this method returns the * package name of the element type. If this class represents a primitive * type or void then the package name "{@code java.lang}" is returned. * * @return the fully qualified package name * * @since 9 * @spec JPMS * @jls 6.7 Fully Qualified Names */ public String getPackageName() { String pn = this.packageName; if (pn == null) { Class<?> c = this; while (c.isArray()) { c = c.getComponentType(); } if (c.isPrimitive()) { pn = "java.lang"; } else { String cn = c.getName(); int dot = cn.lastIndexOf('.'); pn = (dot != -1) ? cn.substring(0, dot).intern() : ""; } this.packageName = pn; } return pn; } // cached package name private transient String packageName; /** * Returns the interfaces directly implemented by the class or interface * represented by this object. * * <p>If this object represents a class, the return value is an array * containing objects representing all interfaces directly implemented by * the class. The order of the interface objects in the array corresponds * to the order of the interface names in the {@code implements} clause of * the declaration of the class represented by this object. For example, * given the declaration: * <blockquote> * {@code class Shimmer implements FloorWax, DessertTopping { ... }} * </blockquote> * suppose the value of {@code s} is an instance of * {@code Shimmer}; the value of the expression: * <blockquote> * {@code s.getClass().getInterfaces()[0]} * </blockquote> * is the {@code Class} object that represents interface * {@code FloorWax}; and the value of: * <blockquote> * {@code s.getClass().getInterfaces()[1]} * </blockquote> * is the {@code Class} object that represents interface * {@code DessertTopping}. * * <p>If this object represents an interface, the array contains objects * representing all interfaces directly extended by the interface. The * order of the interface objects in the array corresponds to the order of * the interface names in the {@code extends} clause of the declaration of * the interface represented by this object. * * <p>If this object represents a class or interface that implements no * interfaces, the method returns an array of length 0. * * <p>If this object represents a primitive type or void, the method * returns an array of length 0. * * <p>If this {@code Class} object represents an array type, the * interfaces {@code Cloneable} and {@code java.io.Serializable} are * returned in that order. * * @return an array of interfaces directly implemented by this class */ public Class<?>[] getInterfaces() { // defensively copy before handing over to user code return getInterfaces(true); } private Class<?>[] getInterfaces(boolean cloneArray) { ReflectionData<T> rd = reflectionData(); if (rd == null) { // no cloning required return getInterfaces0(); } else { Class<?>[] interfaces = rd.interfaces; if (interfaces == null) { interfaces = getInterfaces0(); rd.interfaces = interfaces; } // defensively copy if requested return cloneArray ? interfaces.clone() : interfaces; } } private native Class<?>[] getInterfaces0(); /** * Returns the {@code Type}s representing the interfaces * directly implemented by the class or interface represented by * this object. * * <p>If a superinterface is a parameterized type, the * {@code Type} object returned for it must accurately reflect * the actual type arguments used in the source code. The * parameterized type representing each superinterface is created * if it had not been created before. See the declaration of * {@link java.lang.reflect.ParameterizedType ParameterizedType} * for the semantics of the creation process for parameterized * types. * * <p>If this object represents a class, the return value is an array * containing objects representing all interfaces directly implemented by * the class. The order of the interface objects in the array corresponds * to the order of the interface names in the {@code implements} clause of * the declaration of the class represented by this object. * * <p>If this object represents an interface, the array contains objects * representing all interfaces directly extended by the interface. The * order of the interface objects in the array corresponds to the order of * the interface names in the {@code extends} clause of the declaration of * the interface represented by this object. * * <p>If this object represents a class or interface that implements no * interfaces, the method returns an array of length 0. * * <p>If this object represents a primitive type or void, the method * returns an array of length 0. * * <p>If this {@code Class} object represents an array type, the * interfaces {@code Cloneable} and {@code java.io.Serializable} are * returned in that order. * * @throws java.lang.reflect.GenericSignatureFormatError * if the generic class signature does not conform to the format * specified in * <cite>The Java™ Virtual Machine Specification</cite> * @throws TypeNotPresentException if any of the generic * superinterfaces refers to a non-existent type declaration * @throws java.lang.reflect.MalformedParameterizedTypeException * if any of the generic superinterfaces refer to a parameterized * type that cannot be instantiated for any reason * @return an array of interfaces directly implemented by this class * @since 1.5 */ public Type[] getGenericInterfaces() { ClassRepository info = getGenericInfo(); return (info == null) ? getInterfaces() : info.getSuperInterfaces(); } /** * Returns the {@code Class} representing the component type of an * array. If this class does not represent an array class this method * returns null. * * @return the {@code Class} representing the component type of this * class if this class is an array * @see java.lang.reflect.Array * @since 1.1 */ public Class<?> getComponentType() { // Only return for array types. Storage may be reused for Class for instance types. if (isArray()) { return componentType; } else { return null; } } private final Class<?> componentType; /** * Returns the Java language modifiers for this class or interface, encoded * in an integer. The modifiers consist of the Java Virtual Machine's * constants for {@code public}, {@code protected}, * {@code private}, {@code final}, {@code static}, * {@code abstract} and {@code interface}; they should be decoded * using the methods of class {@code Modifier}. * * <p> If the underlying class is an array class, then its * {@code public}, {@code private} and {@code protected} * modifiers are the same as those of its component type. If this * {@code Class} represents a primitive type or void, its * {@code public} modifier is always {@code true}, and its * {@code protected} and {@code private} modifiers are always * {@code false}. If this object represents an array class, a * primitive type or void, then its {@code final} modifier is always * {@code true} and its interface modifier is always * {@code false}. The values of its other modifiers are not determined * by this specification. * * <p> The modifier encodings are defined in <em>The Java Virtual Machine * Specification</em>, table 4.1. * * @return the {@code int} representing the modifiers for this class * @see java.lang.reflect.Modifier * @since 1.1 */ @HotSpotIntrinsicCandidate public native int getModifiers(); /** * Gets the signers of this class. * * @return the signers of this class, or null if there are no signers. In * particular, this method returns null if this object represents * a primitive type or void. * @since 1.1 */ public native Object[] getSigners(); /** * Set the signers of this class. */ native void setSigners(Object[] signers); /** * If this {@code Class} object represents a local or anonymous * class within a method, returns a {@link * java.lang.reflect.Method Method} object representing the * immediately enclosing method of the underlying class. Returns * {@code null} otherwise. * * In particular, this method returns {@code null} if the underlying * class is a local or anonymous class immediately enclosed by a type * declaration, instance initializer or static initializer. * * @return the immediately enclosing method of the underlying class, if * that class is a local or anonymous class; otherwise {@code null}. * * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of the enclosing class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the methods within the enclosing class * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the enclosing class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of the enclosing class * * </ul> * @since 1.5 */ @CallerSensitive public Method getEnclosingMethod() throws SecurityException { EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo(); if (enclosingInfo == null) return null; else { if (!enclosingInfo.isMethod()) return null; MethodRepository typeInfo = MethodRepository.make(enclosingInfo.getDescriptor(), getFactory()); Class<?> returnType = toClass(typeInfo.getReturnType()); Type[] parameterTypes = typeInfo.getParameterTypes(); Class<?>[] parameterClasses = new Class<?>[parameterTypes.length]; // Convert Types to Classes; returned types *should* // be class objects since the methodDescriptor's used // don't have generics information for (int i = 0; i < parameterClasses.length; i++) parameterClasses[i] = toClass(parameterTypes[i]); // Perform access check final Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass(); SecurityManager sm = System.getSecurityManager(); if (sm != null) { enclosingCandidate.checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true); } Method[] candidates = enclosingCandidate.privateGetDeclaredMethods(false); /* * Loop over all declared methods; match method name, * number of and type of parameters, *and* return * type. Matching return type is also necessary * because of covariant returns, etc. */ ReflectionFactory fact = getReflectionFactory(); for (Method m : candidates) { if (m.getName().equals(enclosingInfo.getName()) && arrayContentsEq(parameterClasses, fact.getExecutableSharedParameterTypes(m))) { // finally, check return type if (m.getReturnType().equals(returnType)) { return fact.copyMethod(m); } } } throw new InternalError("Enclosing method not found"); } } private native Object[] getEnclosingMethod0(); private EnclosingMethodInfo getEnclosingMethodInfo() { Object[] enclosingInfo = getEnclosingMethod0(); if (enclosingInfo == null) return null; else { return new EnclosingMethodInfo(enclosingInfo); } } private static final class EnclosingMethodInfo { private final Class<?> enclosingClass; private final String name; private final String descriptor; static void validate(Object[] enclosingInfo) { if (enclosingInfo.length != 3) throw new InternalError("Malformed enclosing method information"); try { // The array is expected to have three elements: // the immediately enclosing class Class<?> enclosingClass = (Class<?>) enclosingInfo[0]; assert (enclosingClass != null); // the immediately enclosing method or constructor's // name (can be null). String name = (String) enclosingInfo[1]; // the immediately enclosing method or constructor's // descriptor (null iff name is). String descriptor = (String) enclosingInfo[2]; assert ((name != null && descriptor != null) || name == descriptor); } catch (ClassCastException cce) { throw new InternalError("Invalid type in enclosing method information", cce); } } EnclosingMethodInfo(Object[] enclosingInfo) { validate(enclosingInfo); this.enclosingClass = (Class<?>) enclosingInfo[0]; this.name = (String) enclosingInfo[1]; this.descriptor = (String) enclosingInfo[2]; } boolean isPartial() { return enclosingClass == null || name == null || descriptor == null; } boolean isConstructor() { return !isPartial() && "<init>".equals(name); } boolean isMethod() { return !isPartial() && !isConstructor() && !"<clinit>".equals(name); } Class<?> getEnclosingClass() { return enclosingClass; } String getName() { return name; } String getDescriptor() { return descriptor; } } private static Class<?> toClass(Type o) { if (o instanceof GenericArrayType) return Array.newInstance(toClass(((GenericArrayType) o).getGenericComponentType()), 0).getClass(); return (Class<?>) o; } /** * If this {@code Class} object represents a local or anonymous * class within a constructor, returns a {@link * java.lang.reflect.Constructor Constructor} object representing * the immediately enclosing constructor of the underlying * class. Returns {@code null} otherwise. In particular, this * method returns {@code null} if the underlying class is a local * or anonymous class immediately enclosed by a type declaration, * instance initializer or static initializer. * * @return the immediately enclosing constructor of the underlying class, if * that class is a local or anonymous class; otherwise {@code null}. * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of the enclosing class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the constructors within the enclosing class * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the enclosing class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of the enclosing class * * </ul> * @since 1.5 */ @CallerSensitive public Constructor<?> getEnclosingConstructor() throws SecurityException { EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo(); if (enclosingInfo == null) return null; else { if (!enclosingInfo.isConstructor()) return null; ConstructorRepository typeInfo = ConstructorRepository.make(enclosingInfo.getDescriptor(), getFactory()); Type[] parameterTypes = typeInfo.getParameterTypes(); Class<?>[] parameterClasses = new Class<?>[parameterTypes.length]; // Convert Types to Classes; returned types *should* // be class objects since the methodDescriptor's used // don't have generics information for (int i = 0; i < parameterClasses.length; i++) parameterClasses[i] = toClass(parameterTypes[i]); // Perform access check final Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass(); SecurityManager sm = System.getSecurityManager(); if (sm != null) { enclosingCandidate.checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true); } Constructor<?>[] candidates = enclosingCandidate.privateGetDeclaredConstructors(false); /* * Loop over all declared constructors; match number * of and type of parameters. */ ReflectionFactory fact = getReflectionFactory(); for (Constructor<?> c : candidates) { if (arrayContentsEq(parameterClasses, fact.getExecutableSharedParameterTypes(c))) { return fact.copyConstructor(c); } } throw new InternalError("Enclosing constructor not found"); } } /** * If the class or interface represented by this {@code Class} object * is a member of another class, returns the {@code Class} object * representing the class in which it was declared. This method returns * null if this class or interface is not a member of any other class. If * this {@code Class} object represents an array class, a primitive * type, or void,then this method returns null. * * @return the declaring class for this class * @throws SecurityException * If a security manager, <i>s</i>, is present and the caller's * class loader is not the same as or an ancestor of the class * loader for the declaring class and invocation of {@link * SecurityManager#checkPackageAccess s.checkPackageAccess()} * denies access to the package of the declaring class * @since 1.1 */ @CallerSensitive public Class<?> getDeclaringClass() throws SecurityException { final Class<?> candidate = getDeclaringClass0(); if (candidate != null) { SecurityManager sm = System.getSecurityManager(); if (sm != null) { candidate.checkPackageAccess(sm, ClassLoader.getClassLoader(Reflection.getCallerClass()), true); } } return candidate; } private native Class<?> getDeclaringClass0(); /** * Returns the immediately enclosing class of the underlying * class. If the underlying class is a top level class this * method returns {@code null}. * @return the immediately enclosing class of the underlying class * @exception SecurityException * If a security manager, <i>s</i>, is present and the caller's * class loader is not the same as or an ancestor of the class * loader for the enclosing class and invocation of {@link * SecurityManager#checkPackageAccess s.checkPackageAccess()} * denies access to the package of the enclosing class * @since 1.5 */ @CallerSensitive public Class<?> getEnclosingClass() throws SecurityException { // There are five kinds of classes (or interfaces): // a) Top level classes // b) Nested classes (static member classes) // c) Inner classes (non-static member classes) // d) Local classes (named classes declared within a method) // e) Anonymous classes // JVM Spec 4.7.7: A class must have an EnclosingMethod // attribute if and only if it is a local class or an // anonymous class. EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo(); Class<?> enclosingCandidate; if (enclosingInfo == null) { // This is a top level or a nested class or an inner class (a, b, or c) enclosingCandidate = getDeclaringClass0(); } else { Class<?> enclosingClass = enclosingInfo.getEnclosingClass(); // This is a local class or an anonymous class (d or e) if (enclosingClass == this || enclosingClass == null) throw new InternalError("Malformed enclosing method information"); else enclosingCandidate = enclosingClass; } if (enclosingCandidate != null) { SecurityManager sm = System.getSecurityManager(); if (sm != null) { enclosingCandidate.checkPackageAccess(sm, ClassLoader.getClassLoader(Reflection.getCallerClass()), true); } } return enclosingCandidate; } /** * Returns the simple name of the underlying class as given in the * source code. Returns an empty string if the underlying class is * anonymous. * * <p>The simple name of an array is the simple name of the * component type with "[]" appended. In particular the simple * name of an array whose component type is anonymous is "[]". * * @return the simple name of the underlying class * @since 1.5 */ public String getSimpleName() { ReflectionData<T> rd = reflectionData(); String simpleName = rd.simpleName; if (simpleName == null) { rd.simpleName = simpleName = getSimpleName0(); } return simpleName; } private String getSimpleName0() { if (isArray()) { return getComponentType().getSimpleName() + "[]"; } String simpleName = getSimpleBinaryName(); if (simpleName == null) { // top level class simpleName = getName(); simpleName = simpleName.substring(simpleName.lastIndexOf('.') + 1); // strip the package name } return simpleName; } /** * Return an informative string for the name of this type. * * @return an informative string for the name of this type * @since 1.8 */ public String getTypeName() { if (isArray()) { try { Class<?> cl = this; int dimensions = 0; do { dimensions++; cl = cl.getComponentType(); } while (cl.isArray()); return cl.getName() + "[]".repeat(dimensions); } catch (Throwable e) { /*FALLTHRU*/ } } return getName(); } /** * Returns the canonical name of the underlying class as * defined by the Java Language Specification. Returns null if * the underlying class does not have a canonical name (i.e., if * it is a local or anonymous class or an array whose component * type does not have a canonical name). * @return the canonical name of the underlying class if it exists, and * {@code null} otherwise. * @since 1.5 */ public String getCanonicalName() { ReflectionData<T> rd = reflectionData(); String canonicalName = rd.canonicalName; if (canonicalName == null) { rd.canonicalName = canonicalName = getCanonicalName0(); } return canonicalName == ReflectionData.NULL_SENTINEL ? null : canonicalName; } private String getCanonicalName0() { if (isArray()) { String canonicalName = getComponentType().getCanonicalName(); if (canonicalName != null) return canonicalName + "[]"; else return ReflectionData.NULL_SENTINEL; } if (isLocalOrAnonymousClass()) return ReflectionData.NULL_SENTINEL; Class<?> enclosingClass = getEnclosingClass(); if (enclosingClass == null) { // top level class return getName(); } else { String enclosingName = enclosingClass.getCanonicalName(); if (enclosingName == null) return ReflectionData.NULL_SENTINEL; return enclosingName + "." + getSimpleName(); } } /** * Returns {@code true} if and only if the underlying class * is an anonymous class. * * @return {@code true} if and only if this class is an anonymous class. * @since 1.5 */ public boolean isAnonymousClass() { return !isArray() && isLocalOrAnonymousClass() && getSimpleBinaryName0() == null; } /** * Returns {@code true} if and only if the underlying class * is a local class. * * @return {@code true} if and only if this class is a local class. * @since 1.5 */ public boolean isLocalClass() { return isLocalOrAnonymousClass() && (isArray() || getSimpleBinaryName0() != null); } /** * Returns {@code true} if and only if the underlying class * is a member class. * * @return {@code true} if and only if this class is a member class. * @since 1.5 */ public boolean isMemberClass() { return !isLocalOrAnonymousClass() && getDeclaringClass0() != null; } /** * Returns the "simple binary name" of the underlying class, i.e., * the binary name without the leading enclosing class name. * Returns {@code null} if the underlying class is a top level * class. */ private String getSimpleBinaryName() { if (isTopLevelClass()) return null; String name = getSimpleBinaryName0(); if (name == null) // anonymous class return ""; return name; } private native String getSimpleBinaryName0(); /** * Returns {@code true} if this is a top level class. Returns {@code false} * otherwise. */ private boolean isTopLevelClass() { return !isLocalOrAnonymousClass() && getDeclaringClass0() == null; } /** * Returns {@code true} if this is a local class or an anonymous * class. Returns {@code false} otherwise. */ private boolean isLocalOrAnonymousClass() { // JVM Spec 4.7.7: A class must have an EnclosingMethod // attribute if and only if it is a local class or an // anonymous class. return hasEnclosingMethodInfo(); } private boolean hasEnclosingMethodInfo() { Object[] enclosingInfo = getEnclosingMethod0(); if (enclosingInfo != null) { EnclosingMethodInfo.validate(enclosingInfo); return true; } return false; } /** * Returns an array containing {@code Class} objects representing all * the public classes and interfaces that are members of the class * represented by this {@code Class} object. This includes public * class and interface members inherited from superclasses and public class * and interface members declared by the class. This method returns an * array of length 0 if this {@code Class} object has no public member * classes or interfaces. This method also returns an array of length 0 if * this {@code Class} object represents a primitive type, an array * class, or void. * * @return the array of {@code Class} objects representing the public * members of this class * @throws SecurityException * If a security manager, <i>s</i>, is present and * the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class. * * @since 1.1 */ @CallerSensitive public Class<?>[] getClasses() { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), false); } // Privileged so this implementation can look at DECLARED classes, // something the caller might not have privilege to do. The code here // is allowed to look at DECLARED classes because (1) it does not hand // out anything other than public members and (2) public member access // has already been ok'd by the SecurityManager. return java.security.AccessController.doPrivileged(new java.security.PrivilegedAction<>() { public Class<?>[] run() { List<Class<?>> list = new ArrayList<>(); Class<?> currentClass = Class.this; while (currentClass != null) { for (Class<?> m : currentClass.getDeclaredClasses()) { if (Modifier.isPublic(m.getModifiers())) { list.add(m); } } currentClass = currentClass.getSuperclass(); } return list.toArray(new Class<?>[0]); } }); } /** * Returns an array containing {@code Field} objects reflecting all * the accessible public fields of the class or interface represented by * this {@code Class} object. * * <p> If this {@code Class} object represents a class or interface with * no accessible public fields, then this method returns an array of length * 0. * * <p> If this {@code Class} object represents a class, then this method * returns the public fields of the class and of all its superclasses and * superinterfaces. * * <p> If this {@code Class} object represents an interface, then this * method returns the fields of the interface and of all its * superinterfaces. * * <p> If this {@code Class} object represents an array type, a primitive * type, or void, then this method returns an array of length 0. * * <p> The elements in the returned array are not sorted and are not in any * particular order. * * @return the array of {@code Field} objects representing the * public fields * @throws SecurityException * If a security manager, <i>s</i>, is present and * the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class. * * @since 1.1 * @jls 8.2 Class Members * @jls 8.3 Field Declarations */ @CallerSensitive public Field[] getFields() throws SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true); } return copyFields(privateGetPublicFields()); } /** * Returns an array containing {@code Method} objects reflecting all the * public methods of the class or interface represented by this {@code * Class} object, including those declared by the class or interface and * those inherited from superclasses and superinterfaces. * * <p> If this {@code Class} object represents an array type, then the * returned array has a {@code Method} object for each of the public * methods inherited by the array type from {@code Object}. It does not * contain a {@code Method} object for {@code clone()}. * * <p> If this {@code Class} object represents an interface then the * returned array does not contain any implicitly declared methods from * {@code Object}. Therefore, if no methods are explicitly declared in * this interface or any of its superinterfaces then the returned array * has length 0. (Note that a {@code Class} object which represents a class * always has public methods, inherited from {@code Object}.) * * <p> The returned array never contains methods with names "{@code <init>}" * or "{@code <clinit>}". * * <p> The elements in the returned array are not sorted and are not in any * particular order. * * <p> Generally, the result is computed as with the following 4 step algorithm. * Let C be the class or interface represented by this {@code Class} object: * <ol> * <li> A union of methods is composed of: * <ol type="a"> * <li> C's declared public instance and static methods as returned by * {@link #getDeclaredMethods()} and filtered to include only public * methods.</li> * <li> If C is a class other than {@code Object}, then include the result * of invoking this algorithm recursively on the superclass of C.</li> * <li> Include the results of invoking this algorithm recursively on all * direct superinterfaces of C, but include only instance methods.</li> * </ol></li> * <li> Union from step 1 is partitioned into subsets of methods with same * signature (name, parameter types) and return type.</li> * <li> Within each such subset only the most specific methods are selected. * Let method M be a method from a set of methods with same signature * and return type. M is most specific if there is no such method * N != M from the same set, such that N is more specific than M. * N is more specific than M if: * <ol type="a"> * <li> N is declared by a class and M is declared by an interface; or</li> * <li> N and M are both declared by classes or both by interfaces and * N's declaring type is the same as or a subtype of M's declaring type * (clearly, if M's and N's declaring types are the same type, then * M and N are the same method).</li> * </ol></li> * <li> The result of this algorithm is the union of all selected methods from * step 3.</li> * </ol> * * @apiNote There may be more than one method with a particular name * and parameter types in a class because while the Java language forbids a * class to declare multiple methods with the same signature but different * return types, the Java virtual machine does not. This * increased flexibility in the virtual machine can be used to * implement various language features. For example, covariant * returns can be implemented with {@linkplain * java.lang.reflect.Method#isBridge bridge methods}; the bridge * method and the overriding method would have the same * signature but different return types. * * @return the array of {@code Method} objects representing the * public methods of this class * @throws SecurityException * If a security manager, <i>s</i>, is present and * the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class. * * @jls 8.2 Class Members * @jls 8.4 Method Declarations * @since 1.1 */ @CallerSensitive public Method[] getMethods() throws SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true); } return copyMethods(privateGetPublicMethods()); } /** * Returns an array containing {@code Constructor} objects reflecting * all the public constructors of the class represented by this * {@code Class} object. An array of length 0 is returned if the * class has no public constructors, or if the class is an array class, or * if the class reflects a primitive type or void. * * Note that while this method returns an array of {@code * Constructor<T>} objects (that is an array of constructors from * this class), the return type of this method is {@code * Constructor<?>[]} and <em>not</em> {@code Constructor<T>[]} as * might be expected. This less informative return type is * necessary since after being returned from this method, the * array could be modified to hold {@code Constructor} objects for * different classes, which would violate the type guarantees of * {@code Constructor<T>[]}. * * @return the array of {@code Constructor} objects representing the * public constructors of this class * @throws SecurityException * If a security manager, <i>s</i>, is present and * the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class. * * @since 1.1 */ @CallerSensitive public Constructor<?>[] getConstructors() throws SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true); } return copyConstructors(privateGetDeclaredConstructors(true)); } /** * Returns a {@code Field} object that reflects the specified public member * field of the class or interface represented by this {@code Class} * object. The {@code name} parameter is a {@code String} specifying the * simple name of the desired field. * * <p> The field to be reflected is determined by the algorithm that * follows. Let C be the class or interface represented by this object: * * <OL> * <LI> If C declares a public field with the name specified, that is the * field to be reflected.</LI> * <LI> If no field was found in step 1 above, this algorithm is applied * recursively to each direct superinterface of C. The direct * superinterfaces are searched in the order they were declared.</LI> * <LI> If no field was found in steps 1 and 2 above, and C has a * superclass S, then this algorithm is invoked recursively upon S. * If C has no superclass, then a {@code NoSuchFieldException} * is thrown.</LI> * </OL> * * <p> If this {@code Class} object represents an array type, then this * method does not find the {@code length} field of the array type. * * @param name the field name * @return the {@code Field} object of this class specified by * {@code name} * @throws NoSuchFieldException if a field with the specified name is * not found. * @throws NullPointerException if {@code name} is {@code null} * @throws SecurityException * If a security manager, <i>s</i>, is present and * the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class. * * @since 1.1 * @jls 8.2 Class Members * @jls 8.3 Field Declarations */ @CallerSensitive public Field getField(String name) throws NoSuchFieldException, SecurityException { Objects.requireNonNull(name); SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true); } Field field = getField0(name); if (field == null) { throw new NoSuchFieldException(name); } return getReflectionFactory().copyField(field); } /** * Returns a {@code Method} object that reflects the specified public * member method of the class or interface represented by this * {@code Class} object. The {@code name} parameter is a * {@code String} specifying the simple name of the desired method. The * {@code parameterTypes} parameter is an array of {@code Class} * objects that identify the method's formal parameter types, in declared * order. If {@code parameterTypes} is {@code null}, it is * treated as if it were an empty array. * * <p> If this {@code Class} object represents an array type, then this * method finds any public method inherited by the array type from * {@code Object} except method {@code clone()}. * * <p> If this {@code Class} object represents an interface then this * method does not find any implicitly declared method from * {@code Object}. Therefore, if no methods are explicitly declared in * this interface or any of its superinterfaces, then this method does not * find any method. * * <p> This method does not find any method with name "{@code <init>}" or * "{@code <clinit>}". * * <p> Generally, the method to be reflected is determined by the 4 step * algorithm that follows. * Let C be the class or interface represented by this {@code Class} object: * <ol> * <li> A union of methods is composed of: * <ol type="a"> * <li> C's declared public instance and static methods as returned by * {@link #getDeclaredMethods()} and filtered to include only public * methods that match given {@code name} and {@code parameterTypes}</li> * <li> If C is a class other than {@code Object}, then include the result * of invoking this algorithm recursively on the superclass of C.</li> * <li> Include the results of invoking this algorithm recursively on all * direct superinterfaces of C, but include only instance methods.</li> * </ol></li> * <li> This union is partitioned into subsets of methods with same * return type (the selection of methods from step 1 also guarantees that * they have the same method name and parameter types).</li> * <li> Within each such subset only the most specific methods are selected. * Let method M be a method from a set of methods with same VM * signature (return type, name, parameter types). * M is most specific if there is no such method N != M from the same * set, such that N is more specific than M. N is more specific than M * if: * <ol type="a"> * <li> N is declared by a class and M is declared by an interface; or</li> * <li> N and M are both declared by classes or both by interfaces and * N's declaring type is the same as or a subtype of M's declaring type * (clearly, if M's and N's declaring types are the same type, then * M and N are the same method).</li> * </ol></li> * <li> The result of this algorithm is chosen arbitrarily from the methods * with most specific return type among all selected methods from step 3. * Let R be a return type of a method M from the set of all selected methods * from step 3. M is a method with most specific return type if there is * no such method N != M from the same set, having return type S != R, * such that S is a subtype of R as determined by * R.class.{@link #isAssignableFrom}(S.class). * </ol> * * @apiNote There may be more than one method with matching name and * parameter types in a class because while the Java language forbids a * class to declare multiple methods with the same signature but different * return types, the Java virtual machine does not. This * increased flexibility in the virtual machine can be used to * implement various language features. For example, covariant * returns can be implemented with {@linkplain * java.lang.reflect.Method#isBridge bridge methods}; the bridge * method and the overriding method would have the same * signature but different return types. This method would return the * overriding method as it would have a more specific return type. * * @param name the name of the method * @param parameterTypes the list of parameters * @return the {@code Method} object that matches the specified * {@code name} and {@code parameterTypes} * @throws NoSuchMethodException if a matching method is not found * or if the name is "<init>"or "<clinit>". * @throws NullPointerException if {@code name} is {@code null} * @throws SecurityException * If a security manager, <i>s</i>, is present and * the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class. * * @jls 8.2 Class Members * @jls 8.4 Method Declarations * @since 1.1 */ @CallerSensitive public Method getMethod(String name, Class<?>... parameterTypes) throws NoSuchMethodException, SecurityException { Objects.requireNonNull(name); SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true); } Method method = getMethod0(name, parameterTypes); if (method == null) { throw new NoSuchMethodException(methodToString(name, parameterTypes)); } return getReflectionFactory().copyMethod(method); } /** * Returns a {@code Constructor} object that reflects the specified * public constructor of the class represented by this {@code Class} * object. The {@code parameterTypes} parameter is an array of * {@code Class} objects that identify the constructor's formal * parameter types, in declared order. * * If this {@code Class} object represents an inner class * declared in a non-static context, the formal parameter types * include the explicit enclosing instance as the first parameter. * * <p> The constructor to reflect is the public constructor of the class * represented by this {@code Class} object whose formal parameter * types match those specified by {@code parameterTypes}. * * @param parameterTypes the parameter array * @return the {@code Constructor} object of the public constructor that * matches the specified {@code parameterTypes} * @throws NoSuchMethodException if a matching method is not found. * @throws SecurityException * If a security manager, <i>s</i>, is present and * the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class. * * @since 1.1 */ @CallerSensitive public Constructor<T> getConstructor(Class<?>... parameterTypes) throws NoSuchMethodException, SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true); } return getReflectionFactory().copyConstructor(getConstructor0(parameterTypes, Member.PUBLIC)); } /** * Returns an array of {@code Class} objects reflecting all the * classes and interfaces declared as members of the class represented by * this {@code Class} object. This includes public, protected, default * (package) access, and private classes and interfaces declared by the * class, but excludes inherited classes and interfaces. This method * returns an array of length 0 if the class declares no classes or * interfaces as members, or if this {@code Class} object represents a * primitive type, an array class, or void. * * @return the array of {@code Class} objects representing all the * declared members of this class * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of this class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the declared classes within this class * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class * * </ul> * * @since 1.1 */ @CallerSensitive public Class<?>[] getDeclaredClasses() throws SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), false); } return getDeclaredClasses0(); } /** * Returns an array of {@code Field} objects reflecting all the fields * declared by the class or interface represented by this * {@code Class} object. This includes public, protected, default * (package) access, and private fields, but excludes inherited fields. * * <p> If this {@code Class} object represents a class or interface with no * declared fields, then this method returns an array of length 0. * * <p> If this {@code Class} object represents an array type, a primitive * type, or void, then this method returns an array of length 0. * * <p> The elements in the returned array are not sorted and are not in any * particular order. * * @return the array of {@code Field} objects representing all the * declared fields of this class * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of this class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the declared fields within this class * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class * * </ul> * * @since 1.1 * @jls 8.2 Class Members * @jls 8.3 Field Declarations */ @CallerSensitive public Field[] getDeclaredFields() throws SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true); } return copyFields(privateGetDeclaredFields(false)); } /** * Returns an array containing {@code Method} objects reflecting all the * declared methods of the class or interface represented by this {@code * Class} object, including public, protected, default (package) * access, and private methods, but excluding inherited methods. * * <p> If this {@code Class} object represents a type that has multiple * declared methods with the same name and parameter types, but different * return types, then the returned array has a {@code Method} object for * each such method. * * <p> If this {@code Class} object represents a type that has a class * initialization method {@code <clinit>}, then the returned array does * <em>not</em> have a corresponding {@code Method} object. * * <p> If this {@code Class} object represents a class or interface with no * declared methods, then the returned array has length 0. * * <p> If this {@code Class} object represents an array type, a primitive * type, or void, then the returned array has length 0. * * <p> The elements in the returned array are not sorted and are not in any * particular order. * * @return the array of {@code Method} objects representing all the * declared methods of this class * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of this class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the declared methods within this class * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class * * </ul> * * @jls 8.2 Class Members * @jls 8.4 Method Declarations * @since 1.1 */ @CallerSensitive public Method[] getDeclaredMethods() throws SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true); } return copyMethods(privateGetDeclaredMethods(false)); } /** * Returns an array of {@code Constructor} objects reflecting all the * constructors declared by the class represented by this * {@code Class} object. These are public, protected, default * (package) access, and private constructors. The elements in the array * returned are not sorted and are not in any particular order. If the * class has a default constructor, it is included in the returned array. * This method returns an array of length 0 if this {@code Class} * object represents an interface, a primitive type, an array class, or * void. * * <p> See <em>The Java Language Specification</em>, section 8.2. * * @return the array of {@code Constructor} objects representing all the * declared constructors of this class * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of this class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the declared constructors within this class * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class * * </ul> * * @since 1.1 */ @CallerSensitive public Constructor<?>[] getDeclaredConstructors() throws SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true); } return copyConstructors(privateGetDeclaredConstructors(false)); } /** * Returns a {@code Field} object that reflects the specified declared * field of the class or interface represented by this {@code Class} * object. The {@code name} parameter is a {@code String} that specifies * the simple name of the desired field. * * <p> If this {@code Class} object represents an array type, then this * method does not find the {@code length} field of the array type. * * @param name the name of the field * @return the {@code Field} object for the specified field in this * class * @throws NoSuchFieldException if a field with the specified name is * not found. * @throws NullPointerException if {@code name} is {@code null} * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of this class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the declared field * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class * * </ul> * * @since 1.1 * @jls 8.2 Class Members * @jls 8.3 Field Declarations */ @CallerSensitive public Field getDeclaredField(String name) throws NoSuchFieldException, SecurityException { Objects.requireNonNull(name); SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true); } Field field = searchFields(privateGetDeclaredFields(false), name); if (field == null) { throw new NoSuchFieldException(name); } return getReflectionFactory().copyField(field); } /** * Returns a {@code Method} object that reflects the specified * declared method of the class or interface represented by this * {@code Class} object. The {@code name} parameter is a * {@code String} that specifies the simple name of the desired * method, and the {@code parameterTypes} parameter is an array of * {@code Class} objects that identify the method's formal parameter * types, in declared order. If more than one method with the same * parameter types is declared in a class, and one of these methods has a * return type that is more specific than any of the others, that method is * returned; otherwise one of the methods is chosen arbitrarily. If the * name is "<init>"or "<clinit>" a {@code NoSuchMethodException} * is raised. * * <p> If this {@code Class} object represents an array type, then this * method does not find the {@code clone()} method. * * @param name the name of the method * @param parameterTypes the parameter array * @return the {@code Method} object for the method of this class * matching the specified name and parameters * @throws NoSuchMethodException if a matching method is not found. * @throws NullPointerException if {@code name} is {@code null} * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of this class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the declared method * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class * * </ul> * * @jls 8.2 Class Members * @jls 8.4 Method Declarations * @since 1.1 */ @CallerSensitive public Method getDeclaredMethod(String name, Class<?>... parameterTypes) throws NoSuchMethodException, SecurityException { Objects.requireNonNull(name); SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true); } Method method = searchMethods(privateGetDeclaredMethods(false), name, parameterTypes); if (method == null) { throw new NoSuchMethodException(methodToString(name, parameterTypes)); } return getReflectionFactory().copyMethod(method); } /** * Returns the list of {@code Method} objects for the declared public * methods of this class or interface that have the specified method name * and parameter types. * * @param name the name of the method * @param parameterTypes the parameter array * @return the list of {@code Method} objects for the public methods of * this class matching the specified name and parameters */ List<Method> getDeclaredPublicMethods(String name, Class<?>... parameterTypes) { Method[] methods = privateGetDeclaredMethods(/* publicOnly */ true); ReflectionFactory factory = getReflectionFactory(); List<Method> result = new ArrayList<>(); for (Method method : methods) { if (method.getName().equals(name) && Arrays.equals(factory.getExecutableSharedParameterTypes(method), parameterTypes)) { result.add(factory.copyMethod(method)); } } return result; } /** * Returns a {@code Constructor} object that reflects the specified * constructor of the class or interface represented by this * {@code Class} object. The {@code parameterTypes} parameter is * an array of {@code Class} objects that identify the constructor's * formal parameter types, in declared order. * * If this {@code Class} object represents an inner class * declared in a non-static context, the formal parameter types * include the explicit enclosing instance as the first parameter. * * @param parameterTypes the parameter array * @return The {@code Constructor} object for the constructor with the * specified parameter list * @throws NoSuchMethodException if a matching method is not found. * @throws SecurityException * If a security manager, <i>s</i>, is present and any of the * following conditions is met: * * <ul> * * <li> the caller's class loader is not the same as the * class loader of this class and invocation of * {@link SecurityManager#checkPermission * s.checkPermission} method with * {@code RuntimePermission("accessDeclaredMembers")} * denies access to the declared constructor * * <li> the caller's class loader is not the same as or an * ancestor of the class loader for the current class and * invocation of {@link SecurityManager#checkPackageAccess * s.checkPackageAccess()} denies access to the package * of this class * * </ul> * * @since 1.1 */ @CallerSensitive public Constructor<T> getDeclaredConstructor(Class<?>... parameterTypes) throws NoSuchMethodException, SecurityException { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true); } return getReflectionFactory().copyConstructor(getConstructor0(parameterTypes, Member.DECLARED)); } /** * Finds a resource with a given name. * * <p> If this class is in a named {@link Module Module} then this method * will attempt to find the resource in the module. This is done by * delegating to the module's class loader {@link * ClassLoader#findResource(String,String) findResource(String,String)} * method, invoking it with the module name and the absolute name of the * resource. Resources in named modules are subject to the rules for * encapsulation specified in the {@code Module} {@link * Module#getResourceAsStream getResourceAsStream} method and so this * method returns {@code null} when the resource is a * non-"{@code .class}" resource in a package that is not open to the * caller's module. * * <p> Otherwise, if this class is not in a named module then the rules for * searching resources associated with a given class are implemented by the * defining {@linkplain ClassLoader class loader} of the class. This method * delegates to this object's class loader. If this object was loaded by * the bootstrap class loader, the method delegates to {@link * ClassLoader#getSystemResourceAsStream}. * * <p> Before delegation, an absolute resource name is constructed from the * given resource name using this algorithm: * * <ul> * * <li> If the {@code name} begins with a {@code '/'} * (<code>'\u002f'</code>), then the absolute name of the resource is the * portion of the {@code name} following the {@code '/'}. * * <li> Otherwise, the absolute name is of the following form: * * <blockquote> * {@code modified_package_name/name} * </blockquote> * * <p> Where the {@code modified_package_name} is the package name of this * object with {@code '/'} substituted for {@code '.'} * (<code>'\u002e'</code>). * * </ul> * * @param name name of the desired resource * @return A {@link java.io.InputStream} object; {@code null} if no * resource with this name is found, the resource is in a package * that is not {@linkplain Module#isOpen(String, Module) open} to at * least the caller module, or access to the resource is denied * by the security manager. * @throws NullPointerException If {@code name} is {@code null} * * @see Module#getResourceAsStream(String) * @since 1.1 * @revised 9 * @spec JPMS */ @CallerSensitive public InputStream getResourceAsStream(String name) { name = resolveName(name); Module thisModule = getModule(); if (thisModule.isNamed()) { // check if resource can be located by caller if (Resources.canEncapsulate(name) && !isOpenToCaller(name, Reflection.getCallerClass())) { return null; } // resource not encapsulated or in package open to caller String mn = thisModule.getName(); ClassLoader cl = getClassLoader0(); try { // special-case built-in class loaders to avoid the // need for a URL connection if (cl == null) { return BootLoader.findResourceAsStream(mn, name); } else if (cl instanceof BuiltinClassLoader) { return ((BuiltinClassLoader) cl).findResourceAsStream(mn, name); } else { URL url = cl.findResource(mn, name); return (url != null) ? url.openStream() : null; } } catch (IOException | SecurityException e) { return null; } } // unnamed module ClassLoader cl = getClassLoader0(); if (cl == null) { return ClassLoader.getSystemResourceAsStream(name); } else { return cl.getResourceAsStream(name); } } /** * Finds a resource with a given name. * * <p> If this class is in a named {@link Module Module} then this method * will attempt to find the resource in the module. This is done by * delegating to the module's class loader {@link * ClassLoader#findResource(String,String) findResource(String,String)} * method, invoking it with the module name and the absolute name of the * resource. Resources in named modules are subject to the rules for * encapsulation specified in the {@code Module} {@link * Module#getResourceAsStream getResourceAsStream} method and so this * method returns {@code null} when the resource is a * non-"{@code .class}" resource in a package that is not open to the * caller's module. * * <p> Otherwise, if this class is not in a named module then the rules for * searching resources associated with a given class are implemented by the * defining {@linkplain ClassLoader class loader} of the class. This method * delegates to this object's class loader. If this object was loaded by * the bootstrap class loader, the method delegates to {@link * ClassLoader#getSystemResource}. * * <p> Before delegation, an absolute resource name is constructed from the * given resource name using this algorithm: * * <ul> * * <li> If the {@code name} begins with a {@code '/'} * (<code>'\u002f'</code>), then the absolute name of the resource is the * portion of the {@code name} following the {@code '/'}. * * <li> Otherwise, the absolute name is of the following form: * * <blockquote> * {@code modified_package_name/name} * </blockquote> * * <p> Where the {@code modified_package_name} is the package name of this * object with {@code '/'} substituted for {@code '.'} * (<code>'\u002e'</code>). * * </ul> * * @param name name of the desired resource * @return A {@link java.net.URL} object; {@code null} if no resource with * this name is found, the resource cannot be located by a URL, the * resource is in a package that is not * {@linkplain Module#isOpen(String, Module) open} to at least the caller * module, or access to the resource is denied by the security * manager. * @throws NullPointerException If {@code name} is {@code null} * @since 1.1 * @revised 9 * @spec JPMS */ @CallerSensitive public URL getResource(String name) { name = resolveName(name); Module thisModule = getModule(); if (thisModule.isNamed()) { // check if resource can be located by caller if (Resources.canEncapsulate(name) && !isOpenToCaller(name, Reflection.getCallerClass())) { return null; } // resource not encapsulated or in package open to caller String mn = thisModule.getName(); ClassLoader cl = getClassLoader0(); try { if (cl == null) { return BootLoader.findResource(mn, name); } else { return cl.findResource(mn, name); } } catch (IOException ioe) { return null; } } // unnamed module ClassLoader cl = getClassLoader0(); if (cl == null) { return ClassLoader.getSystemResource(name); } else { return cl.getResource(name); } } /** * Returns true if a resource with the given name can be located by the * given caller. All resources in a module can be located by code in * the module. For other callers, then the package needs to be open to * the caller. */ private boolean isOpenToCaller(String name, Class<?> caller) { // assert getModule().isNamed(); Module thisModule = getModule(); Module callerModule = (caller != null) ? caller.getModule() : null; if (callerModule != thisModule) { String pn = Resources.toPackageName(name); if (thisModule.getDescriptor().packages().contains(pn)) { if (callerModule == null && !thisModule.isOpen(pn)) { // no caller, package not open return false; } if (!thisModule.isOpen(pn, callerModule)) { // package not open to caller return false; } } } return true; } /** protection domain returned when the internal domain is null */ private static java.security.ProtectionDomain allPermDomain; /** * Returns the {@code ProtectionDomain} of this class. If there is a * security manager installed, this method first calls the security * manager's {@code checkPermission} method with a * {@code RuntimePermission("getProtectionDomain")} permission to * ensure it's ok to get the * {@code ProtectionDomain}. * * @return the ProtectionDomain of this class * * @throws SecurityException * if a security manager exists and its * {@code checkPermission} method doesn't allow * getting the ProtectionDomain. * * @see java.security.ProtectionDomain * @see SecurityManager#checkPermission * @see java.lang.RuntimePermission * @since 1.2 */ public java.security.ProtectionDomain getProtectionDomain() { SecurityManager sm = System.getSecurityManager(); if (sm != null) { sm.checkPermission(SecurityConstants.GET_PD_PERMISSION); } java.security.ProtectionDomain pd = getProtectionDomain0(); if (pd == null) { if (allPermDomain == null) { java.security.Permissions perms = new java.security.Permissions(); perms.add(SecurityConstants.ALL_PERMISSION); allPermDomain = new java.security.ProtectionDomain(null, perms); } pd = allPermDomain; } return pd; } /** * Returns the ProtectionDomain of this class. */ private native java.security.ProtectionDomain getProtectionDomain0(); /* * Return the Virtual Machine's Class object for the named * primitive type. */ static native Class<?> getPrimitiveClass(String name); /* * Check if client is allowed to access members. If access is denied, * throw a SecurityException. * * This method also enforces package access. * * <p> Default policy: allow all clients access with normal Java access * control. * * <p> NOTE: should only be called if a SecurityManager is installed */ private void checkMemberAccess(SecurityManager sm, int which, Class<?> caller, boolean checkProxyInterfaces) { /* Default policy allows access to all {@link Member#PUBLIC} members, * as well as access to classes that have the same class loader as the caller. * In all other cases, it requires RuntimePermission("accessDeclaredMembers") * permission. */ final ClassLoader ccl = ClassLoader.getClassLoader(caller); if (which != Member.PUBLIC) { final ClassLoader cl = getClassLoader0(); if (ccl != cl) { sm.checkPermission(SecurityConstants.CHECK_MEMBER_ACCESS_PERMISSION); } } this.checkPackageAccess(sm, ccl, checkProxyInterfaces); } /* * Checks if a client loaded in ClassLoader ccl is allowed to access this * class under the current package access policy. If access is denied, * throw a SecurityException. * * NOTE: this method should only be called if a SecurityManager is active */ private void checkPackageAccess(SecurityManager sm, final ClassLoader ccl, boolean checkProxyInterfaces) { final ClassLoader cl = getClassLoader0(); if (ReflectUtil.needsPackageAccessCheck(ccl, cl)) { String pkg = this.getPackageName(); if (pkg != null && !pkg.isEmpty()) { // skip the package access check on a proxy class in default proxy package if (!Proxy.isProxyClass(this) || ReflectUtil.isNonPublicProxyClass(this)) { sm.checkPackageAccess(pkg); } } } // check package access on the proxy interfaces if (checkProxyInterfaces && Proxy.isProxyClass(this)) { ReflectUtil.checkProxyPackageAccess(ccl, this.getInterfaces()); } } /** * Add a package name prefix if the name is not absolute Remove leading "/" * if name is absolute */ private String resolveName(String name) { if (!name.startsWith("/")) { Class<?> c = this; while (c.isArray()) { c = c.getComponentType(); } String baseName = c.getPackageName(); if (baseName != null && !baseName.isEmpty()) { name = baseName.replace('.', '/') + "/" + name; } } else { name = name.substring(1); } return name; } /** * Atomic operations support. */ private static class Atomic { // initialize Unsafe machinery here, since we need to call Class.class instance method // and have to avoid calling it in the static initializer of the Class class... private static final Unsafe unsafe = Unsafe.getUnsafe(); // offset of Class.reflectionData instance field private static final long reflectionDataOffset = unsafe.objectFieldOffset(Class.class, "reflectionData"); // offset of Class.annotationType instance field private static final long annotationTypeOffset = unsafe.objectFieldOffset(Class.class, "annotationType"); // offset of Class.annotationData instance field private static final long annotationDataOffset = unsafe.objectFieldOffset(Class.class, "annotationData"); static <T> boolean casReflectionData(Class<?> clazz, SoftReference<ReflectionData<T>> oldData, SoftReference<ReflectionData<T>> newData) { return unsafe.compareAndSetReference(clazz, reflectionDataOffset, oldData, newData); } static <T> boolean casAnnotationType(Class<?> clazz, AnnotationType oldType, AnnotationType newType) { return unsafe.compareAndSetReference(clazz, annotationTypeOffset, oldType, newType); } static <T> boolean casAnnotationData(Class<?> clazz, AnnotationData oldData, AnnotationData newData) { return unsafe.compareAndSetReference(clazz, annotationDataOffset, oldData, newData); } } /** * Reflection support. */ // Reflection data caches various derived names and reflective members. Cached // values may be invalidated when JVM TI RedefineClasses() is called private static class ReflectionData<T> { volatile Field[] declaredFields; volatile Field[] publicFields; volatile Method[] declaredMethods; volatile Method[] publicMethods; volatile Constructor<T>[] declaredConstructors; volatile Constructor<T>[] publicConstructors; // Intermediate results for getFields and getMethods volatile Field[] declaredPublicFields; volatile Method[] declaredPublicMethods; volatile Class<?>[] interfaces; // Cached names String simpleName; String canonicalName; static final String NULL_SENTINEL = new String(); // Value of classRedefinedCount when we created this ReflectionData instance final int redefinedCount; ReflectionData(int redefinedCount) { this.redefinedCount = redefinedCount; } } private transient volatile SoftReference<ReflectionData<T>> reflectionData; // Incremented by the VM on each call to JVM TI RedefineClasses() // that redefines this class or a superclass. private transient volatile int classRedefinedCount; // Lazily create and cache ReflectionData private ReflectionData<T> reflectionData() { SoftReference<ReflectionData<T>> reflectionData = this.reflectionData; int classRedefinedCount = this.classRedefinedCount; ReflectionData<T> rd; if (reflectionData != null && (rd = reflectionData.get()) != null && rd.redefinedCount == classRedefinedCount) { return rd; } // else no SoftReference or cleared SoftReference or stale ReflectionData // -> create and replace new instance return newReflectionData(reflectionData, classRedefinedCount); } private ReflectionData<T> newReflectionData(SoftReference<ReflectionData<T>> oldReflectionData, int classRedefinedCount) { while (true) { ReflectionData<T> rd = new ReflectionData<>(classRedefinedCount); // try to CAS it... if (Atomic.casReflectionData(this, oldReflectionData, new SoftReference<>(rd))) { return rd; } // else retry oldReflectionData = this.reflectionData; classRedefinedCount = this.classRedefinedCount; if (oldReflectionData != null && (rd = oldReflectionData.get()) != null && rd.redefinedCount == classRedefinedCount) { return rd; } } } // Generic signature handling private native String getGenericSignature0(); // Generic info repository; lazily initialized private transient volatile ClassRepository genericInfo; // accessor for factory private GenericsFactory getFactory() { // create scope and factory return CoreReflectionFactory.make(this, ClassScope.make(this)); } // accessor for generic info repository; // generic info is lazily initialized private ClassRepository getGenericInfo() { ClassRepository genericInfo = this.genericInfo; if (genericInfo == null) { String signature = getGenericSignature0(); if (signature == null) { genericInfo = ClassRepository.NONE; } else { genericInfo = ClassRepository.make(signature, getFactory()); } this.genericInfo = genericInfo; } return (genericInfo != ClassRepository.NONE) ? genericInfo : null; } // Annotations handling native byte[] getRawAnnotations(); // Since 1.8 native byte[] getRawTypeAnnotations(); static byte[] getExecutableTypeAnnotationBytes(Executable ex) { return getReflectionFactory().getExecutableTypeAnnotationBytes(ex); } native ConstantPool getConstantPool(); // // // java.lang.reflect.Field handling // // // Returns an array of "root" fields. These Field objects must NOT // be propagated to the outside world, but must instead be copied // via ReflectionFactory.copyField. private Field[] privateGetDeclaredFields(boolean publicOnly) { Field[] res; ReflectionData<T> rd = reflectionData(); if (rd != null) { res = publicOnly ? rd.declaredPublicFields : rd.declaredFields; if (res != null) return res; } // No cached value available; request value from VM res = Reflection.filterFields(this, getDeclaredFields0(publicOnly)); if (rd != null) { if (publicOnly) { rd.declaredPublicFields = res; } else { rd.declaredFields = res; } } return res; } // Returns an array of "root" fields. These Field objects must NOT // be propagated to the outside world, but must instead be copied // via ReflectionFactory.copyField. private Field[] privateGetPublicFields() { Field[] res; ReflectionData<T> rd = reflectionData(); if (rd != null) { res = rd.publicFields; if (res != null) return res; } // Use a linked hash set to ensure order is preserved and // fields from common super interfaces are not duplicated LinkedHashSet<Field> fields = new LinkedHashSet<>(); // Local fields addAll(fields, privateGetDeclaredFields(true)); // Direct superinterfaces, recursively for (Class<?> si : getInterfaces()) { addAll(fields, si.privateGetPublicFields()); } // Direct superclass, recursively Class<?> sc = getSuperclass(); if (sc != null) { addAll(fields, sc.privateGetPublicFields()); } res = fields.toArray(new Field[0]); if (rd != null) { rd.publicFields = res; } return res; } private static void addAll(Collection<Field> c, Field[] o) { for (Field f : o) { c.add(f); } } // // // java.lang.reflect.Constructor handling // // // Returns an array of "root" constructors. These Constructor // objects must NOT be propagated to the outside world, but must // instead be copied via ReflectionFactory.copyConstructor. private Constructor<T>[] privateGetDeclaredConstructors(boolean publicOnly) { Constructor<T>[] res; ReflectionData<T> rd = reflectionData(); if (rd != null) { res = publicOnly ? rd.publicConstructors : rd.declaredConstructors; if (res != null) return res; } // No cached value available; request value from VM if (isInterface()) { @SuppressWarnings("unchecked") Constructor<T>[] temporaryRes = (Constructor<T>[]) new Constructor<?>[0]; res = temporaryRes; } else { res = getDeclaredConstructors0(publicOnly); } if (rd != null) { if (publicOnly) { rd.publicConstructors = res; } else { rd.declaredConstructors = res; } } return res; } // // // java.lang.reflect.Method handling // // // Returns an array of "root" methods. These Method objects must NOT // be propagated to the outside world, but must instead be copied // via ReflectionFactory.copyMethod. private Method[] privateGetDeclaredMethods(boolean publicOnly) { Method[] res; ReflectionData<T> rd = reflectionData(); if (rd != null) { res = publicOnly ? rd.declaredPublicMethods : rd.declaredMethods; if (res != null) return res; } // No cached value available; request value from VM res = Reflection.filterMethods(this, getDeclaredMethods0(publicOnly)); if (rd != null) { if (publicOnly) { rd.declaredPublicMethods = res; } else { rd.declaredMethods = res; } } return res; } // Returns an array of "root" methods. These Method objects must NOT // be propagated to the outside world, but must instead be copied // via ReflectionFactory.copyMethod. private Method[] privateGetPublicMethods() { Method[] res; ReflectionData<T> rd = reflectionData(); if (rd != null) { res = rd.publicMethods; if (res != null) return res; } // No cached value available; compute value recursively. // Start by fetching public declared methods... PublicMethods pms = new PublicMethods(); for (Method m : privateGetDeclaredMethods(/* publicOnly */ true)) { pms.merge(m); } // ...then recur over superclass methods... Class<?> sc = getSuperclass(); if (sc != null) { for (Method m : sc.privateGetPublicMethods()) { pms.merge(m); } } // ...and finally over direct superinterfaces. for (Class<?> intf : getInterfaces(/* cloneArray */ false)) { for (Method m : intf.privateGetPublicMethods()) { // static interface methods are not inherited if (!Modifier.isStatic(m.getModifiers())) { pms.merge(m); } } } res = pms.toArray(); if (rd != null) { rd.publicMethods = res; } return res; } // // Helpers for fetchers of one field, method, or constructor // // This method does not copy the returned Field object! private static Field searchFields(Field[] fields, String name) { for (Field field : fields) { if (field.getName().equals(name)) { return field; } } return null; } // Returns a "root" Field object. This Field object must NOT // be propagated to the outside world, but must instead be copied // via ReflectionFactory.copyField. private Field getField0(String name) { // Note: the intent is that the search algorithm this routine // uses be equivalent to the ordering imposed by // privateGetPublicFields(). It fetches only the declared // public fields for each class, however, to reduce the number // of Field objects which have to be created for the common // case where the field being requested is declared in the // class which is being queried. Field res; // Search declared public fields if ((res = searchFields(privateGetDeclaredFields(true), name)) != null) { return res; } // Direct superinterfaces, recursively Class<?>[] interfaces = getInterfaces(/* cloneArray */ false); for (Class<?> c : interfaces) { if ((res = c.getField0(name)) != null) { return res; } } // Direct superclass, recursively if (!isInterface()) { Class<?> c = getSuperclass(); if (c != null) { if ((res = c.getField0(name)) != null) { return res; } } } return null; } // This method does not copy the returned Method object! private static Method searchMethods(Method[] methods, String name, Class<?>[] parameterTypes) { ReflectionFactory fact = getReflectionFactory(); Method res = null; for (Method m : methods) { if (m.getName().equals(name) && arrayContentsEq(parameterTypes, fact.getExecutableSharedParameterTypes(m)) && (res == null || (res.getReturnType() != m.getReturnType() && res.getReturnType().isAssignableFrom(m.getReturnType())))) res = m; } return res; } private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0]; // Returns a "root" Method object. This Method object must NOT // be propagated to the outside world, but must instead be copied // via ReflectionFactory.copyMethod. private Method getMethod0(String name, Class<?>[] parameterTypes) { PublicMethods.MethodList res = getMethodsRecursive(name, parameterTypes == null ? EMPTY_CLASS_ARRAY : parameterTypes, /* includeStatic */ true); return res == null ? null : res.getMostSpecific(); } // Returns a list of "root" Method objects. These Method objects must NOT // be propagated to the outside world, but must instead be copied // via ReflectionFactory.copyMethod. private PublicMethods.MethodList getMethodsRecursive(String name, Class<?>[] parameterTypes, boolean includeStatic) { // 1st check declared public methods Method[] methods = privateGetDeclaredMethods(/* publicOnly */ true); PublicMethods.MethodList res = PublicMethods.MethodList.filter(methods, name, parameterTypes, includeStatic); // if there is at least one match among declared methods, we need not // search any further as such match surely overrides matching methods // declared in superclass(es) or interface(s). if (res != null) { return res; } // if there was no match among declared methods, // we must consult the superclass (if any) recursively... Class<?> sc = getSuperclass(); if (sc != null) { res = sc.getMethodsRecursive(name, parameterTypes, includeStatic); } // ...and coalesce the superclass methods with methods obtained // from directly implemented interfaces excluding static methods... for (Class<?> intf : getInterfaces(/* cloneArray */ false)) { res = PublicMethods.MethodList.merge(res, intf.getMethodsRecursive(name, parameterTypes, /* includeStatic */ false)); } return res; } // Returns a "root" Constructor object. This Constructor object must NOT // be propagated to the outside world, but must instead be copied // via ReflectionFactory.copyConstructor. private Constructor<T> getConstructor0(Class<?>[] parameterTypes, int which) throws NoSuchMethodException { ReflectionFactory fact = getReflectionFactory(); Constructor<T>[] constructors = privateGetDeclaredConstructors((which == Member.PUBLIC)); for (Constructor<T> constructor : constructors) { if (arrayContentsEq(parameterTypes, fact.getExecutableSharedParameterTypes(constructor))) { return constructor; } } throw new NoSuchMethodException(methodToString("<init>", parameterTypes)); } // // Other helpers and base implementation // private static boolean arrayContentsEq(Object[] a1, Object[] a2) { if (a1 == null) { return a2 == null || a2.length == 0; } if (a2 == null) { return a1.length == 0; } if (a1.length != a2.length) { return false; } for (int i = 0; i < a1.length; i++) { if (a1[i] != a2[i]) { return false; } } return true; } private static Field[] copyFields(Field[] arg) { Field[] out = new Field[arg.length]; ReflectionFactory fact = getReflectionFactory(); for (int i = 0; i < arg.length; i++) { out[i] = fact.copyField(arg[i]); } return out; } private static Method[] copyMethods(Method[] arg) { Method[] out = new Method[arg.length]; ReflectionFactory fact = getReflectionFactory(); for (int i = 0; i < arg.length; i++) { out[i] = fact.copyMethod(arg[i]); } return out; } private static <U> Constructor<U>[] copyConstructors(Constructor<U>[] arg) { Constructor<U>[] out = arg.clone(); ReflectionFactory fact = getReflectionFactory(); for (int i = 0; i < out.length; i++) { out[i] = fact.copyConstructor(out[i]); } return out; } private native Field[] getDeclaredFields0(boolean publicOnly); private native Method[] getDeclaredMethods0(boolean publicOnly); private native Constructor<T>[] getDeclaredConstructors0(boolean publicOnly); private native Class<?>[] getDeclaredClasses0(); /** * Helper method to get the method name from arguments. */ private String methodToString(String name, Class<?>[] argTypes) { return getName() + '.' + name + ((argTypes == null || argTypes.length == 0) ? "()" : Arrays.stream(argTypes).map(c -> c == null ? "null" : c.getName()) .collect(Collectors.joining(",", "(", ")"))); } /** use serialVersionUID from JDK 1.1 for interoperability */ private static final long serialVersionUID = 3206093459760846163L; /** * Class Class is special cased within the Serialization Stream Protocol. * * A Class instance is written initially into an ObjectOutputStream in the * following format: * <pre> * {@code TC_CLASS} ClassDescriptor * A ClassDescriptor is a special cased serialization of * a {@code java.io.ObjectStreamClass} instance. * </pre> * A new handle is generated for the initial time the class descriptor * is written into the stream. Future references to the class descriptor * are written as references to the initial class descriptor instance. * * @see java.io.ObjectStreamClass */ private static final ObjectStreamField[] serialPersistentFields = new ObjectStreamField[0]; /** * Returns the assertion status that would be assigned to this * class if it were to be initialized at the time this method is invoked. * If this class has had its assertion status set, the most recent * setting will be returned; otherwise, if any package default assertion * status pertains to this class, the most recent setting for the most * specific pertinent package default assertion status is returned; * otherwise, if this class is not a system class (i.e., it has a * class loader) its class loader's default assertion status is returned; * otherwise, the system class default assertion status is returned. * <p> * Few programmers will have any need for this method; it is provided * for the benefit of the JRE itself. (It allows a class to determine at * the time that it is initialized whether assertions should be enabled.) * Note that this method is not guaranteed to return the actual * assertion status that was (or will be) associated with the specified * class when it was (or will be) initialized. * * @return the desired assertion status of the specified class. * @see java.lang.ClassLoader#setClassAssertionStatus * @see java.lang.ClassLoader#setPackageAssertionStatus * @see java.lang.ClassLoader#setDefaultAssertionStatus * @since 1.4 */ public boolean desiredAssertionStatus() { ClassLoader loader = getClassLoader0(); // If the loader is null this is a system class, so ask the VM if (loader == null) return desiredAssertionStatus0(this); // If the classloader has been initialized with the assertion // directives, ask it. Otherwise, ask the VM. synchronized (loader.assertionLock) { if (loader.classAssertionStatus != null) { return loader.desiredAssertionStatus(getName()); } } return desiredAssertionStatus0(this); } // Retrieves the desired assertion status of this class from the VM private static native boolean desiredAssertionStatus0(Class<?> clazz); /** * Returns true if and only if this class was declared as an enum in the * source code. * * @return true if and only if this class was declared as an enum in the * source code * @since 1.5 */ public boolean isEnum() { // An enum must both directly extend java.lang.Enum and have // the ENUM bit set; classes for specialized enum constants // don't do the former. return (this.getModifiers() & ENUM) != 0 && this.getSuperclass() == java.lang.Enum.class; } // Fetches the factory for reflective objects private static ReflectionFactory getReflectionFactory() { if (reflectionFactory == null) { reflectionFactory = java.security.AccessController .doPrivileged(new ReflectionFactory.GetReflectionFactoryAction()); } return reflectionFactory; } private static ReflectionFactory reflectionFactory; /** * Returns the elements of this enum class or null if this * Class object does not represent an enum type. * * @return an array containing the values comprising the enum class * represented by this Class object in the order they're * declared, or null if this Class object does not * represent an enum type * @since 1.5 */ public T[] getEnumConstants() { T[] values = getEnumConstantsShared(); return (values != null) ? values.clone() : null; } /** * Returns the elements of this enum class or null if this * Class object does not represent an enum type; * identical to getEnumConstants except that the result is * uncloned, cached, and shared by all callers. */ T[] getEnumConstantsShared() { T[] constants = enumConstants; if (constants == null) { if (!isEnum()) return null; try { final Method values = getMethod("values"); java.security.AccessController.doPrivileged(new java.security.PrivilegedAction<>() { public Void run() { values.setAccessible(true); return null; } }); @SuppressWarnings("unchecked") T[] temporaryConstants = (T[]) values.invoke(null); enumConstants = constants = temporaryConstants; } // These can happen when users concoct enum-like classes // that don't comply with the enum spec. catch (InvocationTargetException | NoSuchMethodException | IllegalAccessException ex) { return null; } } return constants; } private transient volatile T[] enumConstants; /** * Returns a map from simple name to enum constant. This package-private * method is used internally by Enum to implement * {@code public static <T extends Enum<T>> T valueOf(Class<T>, String)} * efficiently. Note that the map is returned by this method is * created lazily on first use. Typically it won't ever get created. */ Map<String, T> enumConstantDirectory() { Map<String, T> directory = enumConstantDirectory; if (directory == null) { T[] universe = getEnumConstantsShared(); if (universe == null) throw new IllegalArgumentException(getName() + " is not an enum type"); directory = new HashMap<>((int) (universe.length / 0.75f) + 1); for (T constant : universe) { directory.put(((Enum<?>) constant).name(), constant); } enumConstantDirectory = directory; } return directory; } private transient volatile Map<String, T> enumConstantDirectory; /** * Casts an object to the class or interface represented * by this {@code Class} object. * * @param obj the object to be cast * @return the object after casting, or null if obj is null * * @throws ClassCastException if the object is not * null and is not assignable to the type T. * * @since 1.5 */ @SuppressWarnings("unchecked") @HotSpotIntrinsicCandidate public T cast(Object obj) { if (obj != null && !isInstance(obj)) throw new ClassCastException(cannotCastMsg(obj)); return (T) obj; } private String cannotCastMsg(Object obj) { return "Cannot cast " + obj.getClass().getName() + " to " + getName(); } /** * Casts this {@code Class} object to represent a subclass of the class * represented by the specified class object. Checks that the cast * is valid, and throws a {@code ClassCastException} if it is not. If * this method succeeds, it always returns a reference to this class object. * * <p>This method is useful when a client needs to "narrow" the type of * a {@code Class} object to pass it to an API that restricts the * {@code Class} objects that it is willing to accept. A cast would * generate a compile-time warning, as the correctness of the cast * could not be checked at runtime (because generic types are implemented * by erasure). * * @param <U> the type to cast this class object to * @param clazz the class of the type to cast this class object to * @return this {@code Class} object, cast to represent a subclass of * the specified class object. * @throws ClassCastException if this {@code Class} object does not * represent a subclass of the specified class (here "subclass" includes * the class itself). * @since 1.5 */ @SuppressWarnings("unchecked") public <U> Class<? extends U> asSubclass(Class<U> clazz) { if (clazz.isAssignableFrom(this)) return (Class<? extends U>) this; else throw new ClassCastException(this.toString()); } /** * @throws NullPointerException {@inheritDoc} * @since 1.5 */ @SuppressWarnings("unchecked") public <A extends Annotation> A getAnnotation(Class<A> annotationClass) { Objects.requireNonNull(annotationClass); return (A) annotationData().annotations.get(annotationClass); } /** * {@inheritDoc} * @throws NullPointerException {@inheritDoc} * @since 1.5 */ @Override public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) { return GenericDeclaration.super.isAnnotationPresent(annotationClass); } /** * @throws NullPointerException {@inheritDoc} * @since 1.8 */ @Override public <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationClass) { Objects.requireNonNull(annotationClass); AnnotationData annotationData = annotationData(); return AnnotationSupport.getAssociatedAnnotations(annotationData.declaredAnnotations, this, annotationClass); } /** * @since 1.5 */ public Annotation[] getAnnotations() { return AnnotationParser.toArray(annotationData().annotations); } /** * @throws NullPointerException {@inheritDoc} * @since 1.8 */ @Override @SuppressWarnings("unchecked") public <A extends Annotation> A getDeclaredAnnotation(Class<A> annotationClass) { Objects.requireNonNull(annotationClass); return (A) annotationData().declaredAnnotations.get(annotationClass); } /** * @throws NullPointerException {@inheritDoc} * @since 1.8 */ @Override public <A extends Annotation> A[] getDeclaredAnnotationsByType(Class<A> annotationClass) { Objects.requireNonNull(annotationClass); return AnnotationSupport.getDirectlyAndIndirectlyPresent(annotationData().declaredAnnotations, annotationClass); } /** * @since 1.5 */ public Annotation[] getDeclaredAnnotations() { return AnnotationParser.toArray(annotationData().declaredAnnotations); } // annotation data that might get invalidated when JVM TI RedefineClasses() is called private static class AnnotationData { final Map<Class<? extends Annotation>, Annotation> annotations; final Map<Class<? extends Annotation>, Annotation> declaredAnnotations; // Value of classRedefinedCount when we created this AnnotationData instance final int redefinedCount; AnnotationData(Map<Class<? extends Annotation>, Annotation> annotations, Map<Class<? extends Annotation>, Annotation> declaredAnnotations, int redefinedCount) { this.annotations = annotations; this.declaredAnnotations = declaredAnnotations; this.redefinedCount = redefinedCount; } } // Annotations cache @SuppressWarnings("UnusedDeclaration") private transient volatile AnnotationData annotationData; private AnnotationData annotationData() { while (true) { // retry loop AnnotationData annotationData = this.annotationData; int classRedefinedCount = this.classRedefinedCount; if (annotationData != null && annotationData.redefinedCount == classRedefinedCount) { return annotationData; } // null or stale annotationData -> optimistically create new instance AnnotationData newAnnotationData = createAnnotationData(classRedefinedCount); // try to install it if (Atomic.casAnnotationData(this, annotationData, newAnnotationData)) { // successfully installed new AnnotationData return newAnnotationData; } } } private AnnotationData createAnnotationData(int classRedefinedCount) { Map<Class<? extends Annotation>, Annotation> declaredAnnotations = AnnotationParser .parseAnnotations(getRawAnnotations(), getConstantPool(), this); Class<?> superClass = getSuperclass(); Map<Class<? extends Annotation>, Annotation> annotations = null; if (superClass != null) { Map<Class<? extends Annotation>, Annotation> superAnnotations = superClass.annotationData().annotations; for (Map.Entry<Class<? extends Annotation>, Annotation> e : superAnnotations.entrySet()) { Class<? extends Annotation> annotationClass = e.getKey(); if (AnnotationType.getInstance(annotationClass).isInherited()) { if (annotations == null) { // lazy construction annotations = new LinkedHashMap<>((Math.max(declaredAnnotations.size(), Math.min(12, declaredAnnotations.size() + superAnnotations.size())) * 4 + 2) / 3); } annotations.put(annotationClass, e.getValue()); } } } if (annotations == null) { // no inherited annotations -> share the Map with declaredAnnotations annotations = declaredAnnotations; } else { // at least one inherited annotation -> declared may override inherited annotations.putAll(declaredAnnotations); } return new AnnotationData(annotations, declaredAnnotations, classRedefinedCount); } // Annotation types cache their internal (AnnotationType) form @SuppressWarnings("UnusedDeclaration") private transient volatile AnnotationType annotationType; boolean casAnnotationType(AnnotationType oldType, AnnotationType newType) { return Atomic.casAnnotationType(this, oldType, newType); } AnnotationType getAnnotationType() { return annotationType; } Map<Class<? extends Annotation>, Annotation> getDeclaredAnnotationMap() { return annotationData().declaredAnnotations; } /* Backing store of user-defined values pertaining to this class. * Maintained by the ClassValue class. */ transient ClassValue.ClassValueMap classValueMap; /** * Returns an {@code AnnotatedType} object that represents the use of a * type to specify the superclass of the entity represented by this {@code * Class} object. (The <em>use</em> of type Foo to specify the superclass * in '... extends Foo' is distinct from the <em>declaration</em> of type * Foo.) * * <p> If this {@code Class} object represents a type whose declaration * does not explicitly indicate an annotated superclass, then the return * value is an {@code AnnotatedType} object representing an element with no * annotations. * * <p> If this {@code Class} represents either the {@code Object} class, an * interface type, an array type, a primitive type, or void, the return * value is {@code null}. * * @return an object representing the superclass * @since 1.8 */ public AnnotatedType getAnnotatedSuperclass() { if (this == Object.class || isInterface() || isArray() || isPrimitive() || this == Void.TYPE) { return null; } return TypeAnnotationParser.buildAnnotatedSuperclass(getRawTypeAnnotations(), getConstantPool(), this); } /** * Returns an array of {@code AnnotatedType} objects that represent the use * of types to specify superinterfaces of the entity represented by this * {@code Class} object. (The <em>use</em> of type Foo to specify a * superinterface in '... implements Foo' is distinct from the * <em>declaration</em> of type Foo.) * * <p> If this {@code Class} object represents a class, the return value is * an array containing objects representing the uses of interface types to * specify interfaces implemented by the class. The order of the objects in * the array corresponds to the order of the interface types used in the * 'implements' clause of the declaration of this {@code Class} object. * * <p> If this {@code Class} object represents an interface, the return * value is an array containing objects representing the uses of interface * types to specify interfaces directly extended by the interface. The * order of the objects in the array corresponds to the order of the * interface types used in the 'extends' clause of the declaration of this * {@code Class} object. * * <p> If this {@code Class} object represents a class or interface whose * declaration does not explicitly indicate any annotated superinterfaces, * the return value is an array of length 0. * * <p> If this {@code Class} object represents either the {@code Object} * class, an array type, a primitive type, or void, the return value is an * array of length 0. * * @return an array representing the superinterfaces * @since 1.8 */ public AnnotatedType[] getAnnotatedInterfaces() { return TypeAnnotationParser.buildAnnotatedInterfaces(getRawTypeAnnotations(), getConstantPool(), this); } private native Class<?> getNestHost0(); /** * Returns the nest host of the <a href=#nest>nest</a> to which the class * or interface represented by this {@code Class} object belongs. * Every class and interface is a member of exactly one nest. * A class or interface that is not recorded as belonging to a nest * belongs to the nest consisting only of itself, and is the nest * host. * * <p>Each of the {@code Class} objects representing array types, * primitive types, and {@code void} returns {@code this} to indicate * that the represented entity belongs to the nest consisting only of * itself, and is the nest host. * * <p>If there is a {@linkplain LinkageError linkage error} accessing * the nest host, or if this class or interface is not enumerated as * a member of the nest by the nest host, then it is considered to belong * to its own nest and {@code this} is returned as the host. * * @apiNote A {@code class} file of version 55.0 or greater may record the * host of the nest to which it belongs by using the {@code NestHost} * attribute (JVMS 4.7.28). Alternatively, a {@code class} file of * version 55.0 or greater may act as a nest host by enumerating the nest's * other members with the * {@code NestMembers} attribute (JVMS 4.7.29). * A {@code class} file of version 54.0 or lower does not use these * attributes. * * @return the nest host of this class or interface * * @throws SecurityException * If the returned class is not the current class, and * if a security manager, <i>s</i>, is present and the caller's * class loader is not the same as or an ancestor of the class * loader for the returned class and invocation of {@link * SecurityManager#checkPackageAccess s.checkPackageAccess()} * denies access to the package of the returned class * @since 11 * @jvms 4.7.28 The {@code NestHost} Attribute * @jvms 4.7.29 The {@code NestMembers} Attribute * @jvms 5.4.4 Access Control */ @CallerSensitive public Class<?> getNestHost() { if (isPrimitive() || isArray()) { return this; } Class<?> host; try { host = getNestHost0(); } catch (LinkageError e) { // if we couldn't load our nest-host then we // act as-if we have no nest-host attribute return this; } // if null then nest membership validation failed, so we // act as-if we have no nest-host attribute if (host == null || host == this) { return this; } // returning a different class requires a security check SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkPackageAccess(sm, ClassLoader.getClassLoader(Reflection.getCallerClass()), true); } return host; } /** * Determines if the given {@code Class} is a nestmate of the * class or interface represented by this {@code Class} object. * Two classes or interfaces are nestmates * if they have the same {@linkplain #getNestHost() nest host}. * * @param c the class to check * @return {@code true} if this class and {@code c} are members of * the same nest; and {@code false} otherwise. * * @since 11 */ public boolean isNestmateOf(Class<?> c) { if (this == c) { return true; } if (isPrimitive() || isArray() || c.isPrimitive() || c.isArray()) { return false; } try { return getNestHost0() == c.getNestHost0(); } catch (LinkageError e) { return false; } } private native Class<?>[] getNestMembers0(); /** * Returns an array containing {@code Class} objects representing all the * classes and interfaces that are members of the nest to which the class * or interface represented by this {@code Class} object belongs. * The {@linkplain #getNestHost() nest host} of that nest is the zeroth * element of the array. Subsequent elements represent any classes or * interfaces that are recorded by the nest host as being members of * the nest; the order of such elements is unspecified. Duplicates are * permitted. * If the nest host of that nest does not enumerate any members, then the * array has a single element containing {@code this}. * * <p>Each of the {@code Class} objects representing array types, * primitive types, and {@code void} returns an array containing only * {@code this}. * * <p>This method validates that, for each class or interface which is * recorded as a member of the nest by the nest host, that class or * interface records itself as a member of that same nest. Any exceptions * that occur during this validation are rethrown by this method. * * @return an array of all classes and interfaces in the same nest as * this class * * @throws LinkageError * If there is any problem loading or validating a nest member or * its nest host * @throws SecurityException * If any returned class is not the current class, and * if a security manager, <i>s</i>, is present and the caller's * class loader is not the same as or an ancestor of the class * loader for that returned class and invocation of {@link * SecurityManager#checkPackageAccess s.checkPackageAccess()} * denies access to the package of that returned class * * @since 11 * @see #getNestHost() */ @CallerSensitive public Class<?>[] getNestMembers() { if (isPrimitive() || isArray()) { return new Class<?>[] { this }; } Class<?>[] members = getNestMembers0(); // Can't actually enable this due to bootstrapping issues // assert(members.length != 1 || members[0] == this); // expected invariant from VM if (members.length > 1) { // If we return anything other than the current class we need // a security check SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkPackageAccess(sm, ClassLoader.getClassLoader(Reflection.getCallerClass()), true); } } return members; } /** * Returns the type descriptor string for this class. * <p> * Note that this is not a strict inverse of {@link #forName}; * distinct classes which share a common name but have different class loaders * will have identical descriptor strings. * * @return the type descriptor representation * @jvms 4.3.2 Field Descriptors * @since 12 */ @Override public String descriptorString() { if (isPrimitive()) return Wrapper.forPrimitiveType(this).basicTypeString(); else if (isArray()) { return "[" + componentType.descriptorString(); } else { return "L" + getName().replace('.', '/') + ";"; } } /** * Returns the component type of this {@code Class}, if it describes * an array type, or {@code null} otherwise. * * @implSpec * Equivalent to {@link Class#getComponentType()}. * * @return a {@code Class} describing the component type, or {@code null} * if this {@code Class} does not describe an array type * @since 12 */ @Override public Class<?> componentType() { return isArray() ? componentType : null; } /** * Returns a {@code Class} for an array type whose component type * is described by this {@linkplain Class}. * * @return a {@code Class} describing the array type * @since 12 */ @Override public Class<?> arrayType() { return Array.newInstance(this, 0).getClass(); } /** * Returns a nominal descriptor for this instance, if one can be * constructed, or an empty {@link Optional} if one cannot be. * * @return An {@link Optional} containing the resulting nominal descriptor, * or an empty {@link Optional} if one cannot be constructed. * @since 12 */ @Override public Optional<ClassDesc> describeConstable() { return Optional.of(ClassDesc.ofDescriptor(descriptorString())); } }