Java Class Loader loadClass(ClassLoader cl, String cName)

Description

Loads the class from the given classloader or returns null (does not throw).

License

Open Source License

Parameter

Parameter	Description
cl	The non-null classloader to load the class from
cName	The fully qualified non-null name of the class to load

Return

The class if it could be loaded from the classloader, or null if it could not be found for any reason

Declaration

public static Class<?> loadClass(ClassLoader cl, String cName) 

Method Source Code

//package com.java2s;
/*//w  ww.  j a  v a2s  . c  o  m
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 * Copyright (c) 2014-2015 Oracle and/or its affiliates. All rights reserved.
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 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
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 * If you wish your version of this file to be governed by only the CDDL or
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 * Version 2] license."  If you don't indicate a single choice of license, a
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import java.lang.reflect.Array;

public class Main {
    /**
     * Loads the class from the given classloader or returns null (does not throw).
     * Property handles array classes as well
     * 
     * @param cl The non-null classloader to load the class from
     * @param cName The fully qualified non-null name of the class to load
     * @return The class if it could be loaded from the classloader, or
     * null if it could not be found for any reason
     */
    public static Class<?> loadClass(ClassLoader cl, String cName) {
        if (cName.startsWith("[")) {
            return loadArrayClass(cl, cName);
        }

        try {
            return cl.loadClass(cName);
        } catch (Throwable th) {
            return null;
        }
    }

    private static Class<?> loadArrayClass(ClassLoader cl, String aName) {
        Class<?> componentType = null;
        int[] dimensions = null;

        int dot = 0;
        while (componentType == null) {
            char dotChar = aName.charAt(dot);
            if (dotChar == '[') {
                dot++;
                continue;
            }

            dimensions = new int[dot];
            for (int lcv = 0; lcv < dot; lcv++) {
                dimensions[lcv] = 0;
            }

            if (dotChar == 'B') {
                componentType = byte.class;
            } else if (dotChar == 'I') {
                componentType = int.class;
            } else if (dotChar == 'J') {
                componentType = long.class;
            } else if (dotChar == 'Z') {
                componentType = boolean.class;
            } else if (dotChar == 'S') {
                componentType = short.class;
            } else if (dotChar == 'C') {
                componentType = char.class;
            } else if (dotChar == 'D') {
                componentType = double.class;
            } else if (dotChar == 'F') {
                componentType = float.class;
            } else {
                if (dotChar != 'L') {
                    throw new IllegalArgumentException("Unknown array type " + aName);
                }

                if (aName.charAt(aName.length() - 1) != ';') {
                    throw new IllegalArgumentException("Badly formed L array expresion: " + aName);
                }

                String cName = aName.substring(dot + 1, aName.length() - 1);

                componentType = loadClass(cl, cName);
                if (componentType == null)
                    return null;
            }
        }

        Object retArray = Array.newInstance(componentType, dimensions);
        return retArray.getClass();
    }
}

Related

1. load(Class serviceClass, ClassLoader loader)
2. load(String className)
3. load(String path, String className)
4. loadAllAutoConfigFiles(ClassLoader classloader)
5. loadArrayClass(ClassLoader cl, String aName)
6. loadClass(final File baseFolder, final String qualifiedType)
7. loadClass(final File classFolder, final String className)
8. loadClass(String className)
9. loadClass(String className)