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Tomcat example source code file (

This example Tomcat source code file ( is included in the "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

class, class, classloader, classnotfoundexception, classnotfoundexception, codesource, inputstream, io, ioexception, jasperloader, net, network, permissioncollection, permissioncollection, security, security, string, string

The Tomcat source code

 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.

package org.apache.jasper.servlet;


import org.apache.jasper.Constants;

 * Class loader for loading servlet class files (corresponding to JSP files) 
 * and tag handler class files (corresponding to tag files).
 * @author Anil K. Vijendran
 * @author Harish Prabandham
 * @author Jean-Francois Arcand
public class JasperLoader extends URLClassLoader {

    private PermissionCollection permissionCollection;
    private CodeSource codeSource;
    private String className;
    private ClassLoader parent;
    private SecurityManager securityManager;

    public JasperLoader(URL[] urls, ClassLoader parent,
			PermissionCollection permissionCollection,
			CodeSource codeSource) {
	super(urls, parent);
	this.permissionCollection = permissionCollection;
	this.codeSource = codeSource;
	this.parent = parent;
	this.securityManager = System.getSecurityManager();

     * Load the class with the specified name.  This method searches for
     * classes in the same manner as <code>loadClass(String, boolean)
     * with <code>false as the second argument.
     * @param name Name of the class to be loaded
     * @exception ClassNotFoundException if the class was not found
    public Class loadClass(String name) throws ClassNotFoundException {

        return (loadClass(name, false));

     * Load the class with the specified name, searching using the following
     * algorithm until it finds and returns the class.  If the class cannot
     * be found, returns <code>ClassNotFoundException.
     * <ul>
     * <li>Call findLoadedClass(String) to check if the
     *     class has already been loaded.  If it has, the same
     *     <code>Class object is returned.
     * <li>If the delegate property is set to true,
     *     call the <code>loadClass() method of the parent class
     *     loader, if any.</li>            
     * <li>Call findClass() to find this class in our locally
     *     defined repositories.</li>      
     * <li>Call the loadClass() method of our parent
     *     class loader, if any.</li>      
     * </ul>
     * If the class was found using the above steps, and the
     * <code>resolve flag is true, this method will then
     * call <code>resolveClass(Class) on the resulting Class object.
     * @param name Name of the class to be loaded
     * @param resolve If <code>true then resolve the class
     * @exception ClassNotFoundException if the class was not found
    public Class loadClass(final String name, boolean resolve)
        throws ClassNotFoundException {

        Class clazz = null;                
        // (0) Check our previously loaded class cache
        clazz = findLoadedClass(name);     
        if (clazz != null) {               
            if (resolve)                   
            return (clazz);        
        // (.5) Permission to access this class when using a SecurityManager
        if (securityManager != null) {     
            int dot = name.lastIndexOf('.');
            if (dot >= 0) {                
                try {        
                    // Do not call the security manager since by default, we grant that package.
                    if (!"org.apache.jasper.runtime".equalsIgnoreCase(name.substring(0,dot))){
                } catch (SecurityException se) {
                    String error = "Security Violation, attempt to use " +
                        "Restricted Class: " + name;
                    throw new ClassNotFoundException(error);

	if( !name.startsWith(Constants.JSP_PACKAGE_NAME) ) {
            // Class is not in org.apache.jsp, therefore, have our
            // parent load it
            clazz = parent.loadClass(name);            
	    if( resolve )
	    return clazz;

	return findClass(name);

     * Delegate to parent
     * @see java.lang.ClassLoader#getResourceAsStream(java.lang.String)
    public InputStream getResourceAsStream(String name) {
        InputStream is = parent.getResourceAsStream(name);
        if (is == null) {
            URL url = findResource(name);
            if (url != null) {
                try {
                    is = url.openStream();
                } catch (IOException e) {
                    is = null;
        return is;
     * Get the Permissions for a CodeSource.
     * Since this ClassLoader is only used for a JSP page in
     * a web application context, we just return our preset
     * PermissionCollection for the web app context.
     * @param codeSource Code source where the code was loaded from
     * @return PermissionCollection for CodeSource
    public final PermissionCollection getPermissions(CodeSource codeSource) {
        return permissionCollection;

Other Tomcat examples (source code examples)

Here is a short list of links related to this Tomcat source code file:

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