Java tutorial
/* * Copyright (c) 2003, 2017, 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.management; import java.security.AccessController; import java.security.PrivilegedAction; /** * The management interface for the runtime system of * the Java virtual machine. * * <p> A Java virtual machine has a single instance of the implementation * class of this interface. This instance implementing this interface is * an <a href="ManagementFactory.html#MXBean">MXBean</a> * that can be obtained by calling * the {@link ManagementFactory#getRuntimeMXBean} method or * from the {@link ManagementFactory#getPlatformMBeanServer * platform MBeanServer} method. * * <p>The {@code ObjectName} for uniquely identifying the MXBean for * the runtime system within an MBeanServer is: * <blockquote> * {@link ManagementFactory#RUNTIME_MXBEAN_NAME * java.lang:type=Runtime} * </blockquote> * * It can be obtained by calling the * {@link PlatformManagedObject#getObjectName} method. * * <p> This interface defines several convenient methods for accessing * system properties about the Java virtual machine. * * @see ManagementFactory#getPlatformMXBeans(Class) * @see <a href="../../../javax/management/package-summary.html"> * JMX Specification.</a> * @see <a href="package-summary.html#examples"> * Ways to Access MXBeans</a> * * @author Mandy Chung * @since 1.5 */ public interface RuntimeMXBean extends PlatformManagedObject { /** * Returns the {@linkplain ProcessHandle#pid process ID} representing * the running Java virtual machine. * * @implSpec The default implementation returns {@link ProcessHandle#pid process ID} * of the {@linkplain ProcessHandle#current current process}. * * @return the process ID representing the running Java virtual machine. * * @since 10 */ public default long getPid() { return AccessController.doPrivileged((PrivilegedAction<Long>) () -> ProcessHandle.current().pid()); } /** * Returns the name representing the running Java virtual machine. * The returned name string can be any arbitrary string and * a Java virtual machine implementation can choose * to embed platform-specific useful information in the * returned name string. Each running virtual machine could have * a different name. * * @return the name representing the running Java virtual machine. */ public String getName(); /** * Returns the Java virtual machine implementation name. * This method is equivalent to {@link System#getProperty * System.getProperty("java.vm.name")}. * * @return the Java virtual machine implementation name. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to this system property. * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperty */ public String getVmName(); /** * Returns the Java virtual machine implementation vendor. * This method is equivalent to {@link System#getProperty * System.getProperty("java.vm.vendor")}. * * @return the Java virtual machine implementation vendor. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to this system property. * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperty */ public String getVmVendor(); /** * Returns the Java virtual machine implementation version. * This method is equivalent to {@link System#getProperty * System.getProperty("java.vm.version")}. * * @return the Java virtual machine implementation version. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to this system property. * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperty */ public String getVmVersion(); /** * Returns the Java virtual machine specification name. * This method is equivalent to {@link System#getProperty * System.getProperty("java.vm.specification.name")}. * * @return the Java virtual machine specification name. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to this system property. * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperty */ public String getSpecName(); /** * Returns the Java virtual machine specification vendor. * This method is equivalent to {@link System#getProperty * System.getProperty("java.vm.specification.vendor")}. * * @return the Java virtual machine specification vendor. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to this system property. * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperty */ public String getSpecVendor(); /** * Returns the Java virtual machine specification version. * This method is equivalent to {@link System#getProperty * System.getProperty("java.vm.specification.version")}. * * @return the Java virtual machine specification version. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to this system property. * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperty */ public String getSpecVersion(); /** * Returns the version of the specification for the management interface * implemented by the running Java virtual machine. * * @return the version of the specification for the management interface * implemented by the running Java virtual machine. */ public String getManagementSpecVersion(); /** * Returns the Java class path that is used by the system class loader * to search for class files. * This method is equivalent to {@link System#getProperty * System.getProperty("java.class.path")}. * * <p> Multiple paths in the Java class path are separated by the * path separator character of the platform of the Java virtual machine * being monitored. * * @return the Java class path. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to this system property. * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperty */ public String getClassPath(); /** * Returns the Java library path. * This method is equivalent to {@link System#getProperty * System.getProperty("java.library.path")}. * * <p> Multiple paths in the Java library path are separated by the * path separator character of the platform of the Java virtual machine * being monitored. * * @return the Java library path. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to this system property. * @see java.lang.SecurityManager#checkPropertyAccess(java.lang.String) * @see java.lang.System#getProperty */ public String getLibraryPath(); /** * Tests if the Java virtual machine supports the boot class path * mechanism used by the bootstrap class loader to search for class * files. * * @return {@code true} if the Java virtual machine supports the * class path mechanism; {@code false} otherwise. */ public boolean isBootClassPathSupported(); /** * Returns the boot class path that is used by the bootstrap class loader * to search for class files. * * <p> Multiple paths in the boot class path are separated by the * path separator character of the platform on which the Java * virtual machine is running. * * <p>A Java virtual machine implementation may not support * the boot class path mechanism for the bootstrap class loader * to search for class files. * The {@link #isBootClassPathSupported} method can be used * to determine if the Java virtual machine supports this method. * * @return the boot class path. * * @throws java.lang.UnsupportedOperationException * if the Java virtual machine does not support this operation. * * @throws java.lang.SecurityException * if a security manager exists and the caller does not have * ManagementPermission("monitor"). */ public String getBootClassPath(); /** * Returns the input arguments passed to the Java virtual machine * which does not include the arguments to the {@code main} method. * This method returns an empty list if there is no input argument * to the Java virtual machine. * <p> * Some Java virtual machine implementations may take input arguments * from multiple different sources: for examples, arguments passed from * the application that launches the Java virtual machine such as * the 'java' command, environment variables, configuration files, etc. * <p> * Typically, not all command-line options to the 'java' command * are passed to the Java virtual machine. * Thus, the returned input arguments may not * include all command-line options. * * <p> * <b>MBeanServer access</b>:<br> * The mapped type of {@code List<String>} is {@code String[]}. * * @return a list of {@code String} objects; each element * is an argument passed to the Java virtual machine. * * @throws java.lang.SecurityException * if a security manager exists and the caller does not have * ManagementPermission("monitor"). */ public java.util.List<String> getInputArguments(); /** * Returns the uptime of the Java virtual machine in milliseconds. * * @return uptime of the Java virtual machine in milliseconds. */ public long getUptime(); /** * Returns the start time of the Java virtual machine in milliseconds. * This method returns the approximate time when the Java virtual * machine started. * * @return start time of the Java virtual machine in milliseconds. * */ public long getStartTime(); /** * Returns a map of names and values of all system properties. * This method calls {@link System#getProperties} to get all * system properties. Properties whose name or value is not * a {@code String} are omitted. * * <p> * <b>MBeanServer access</b>:<br> * The mapped type of {@code Map<String,String>} is * {@link javax.management.openmbean.TabularData TabularData} * with two items in each row as follows: * <table class="striped" style="margin-left:2em"> * <caption style="display:none">Name and Type for each item</caption> * <thead> * <tr> * <th scope="col">Item Name</th> * <th scope="col">Item Type</th> * </tr> * </thead> * <tbody> * <tr style="text-align:left"> * <th scope="row">{@code key}</th> * <td>{@code String}</td> * </tr> * <tr> * <th scope="row">{@code value}</th> * <td>{@code String}</td> * </tr> * </tbody> * </table> * * @return a map of names and values of all system properties. * * @throws java.lang.SecurityException * if a security manager exists and its * {@code checkPropertiesAccess} method doesn't allow access * to the system properties. */ public java.util.Map<String, String> getSystemProperties(); }