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Tomcat example source code file (WebappClassLoader.java)

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

Java - Tomcat tags/keywords

class, classloader, classnotfoundexception, classnotfoundexception, file, file, io, ioexception, jar, malformedurlexception, network, resourceentry, resourceentry, returning, security, sql, string, string, url, util

The Tomcat WebappClassLoader.java 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
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package org.apache.catalina.loader;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FilePermission;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.AccessControlException;
import java.security.AccessController;
import java.security.CodeSource;
import java.security.Permission;
import java.security.PermissionCollection;
import java.security.Policy;
import java.security.PrivilegedAction;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Vector;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.util.jar.Attributes.Name;

import javax.naming.NameClassPair;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.DirContext;

import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.LifecycleListener;
import org.apache.catalina.util.StringManager;
import org.apache.naming.JndiPermission;
import org.apache.naming.resources.Resource;
import org.apache.naming.resources.ResourceAttributes;
import org.apache.tomcat.util.IntrospectionUtils;

/**
 * Specialized web application class loader.
 * <p>
 * This class loader is a full reimplementation of the 
 * <code>URLClassLoader from the JDK. It is desinged to be fully
 * compatible with a normal <code>URLClassLoader, although its internal
 * behavior may be completely different.
 * <p>
 * <strong>IMPLEMENTATION NOTE - This class loader faithfully follows 
 * the delegation model recommended in the specification. The system class 
 * loader will be queried first, then the local repositories, and only then 
 * delegation to the parent class loader will occur. This allows the web 
 * application to override any shared class except the classes from J2SE.
 * Special handling is provided from the JAXP XML parser interfaces, the JNDI
 * interfaces, and the classes from the servlet API, which are never loaded 
 * from the webapp repository.
 * <p>
 * <strong>IMPLEMENTATION NOTE - Due to limitations in Jasper 
 * compilation technology, any repository which contains classes from 
 * the servlet API will be ignored by the class loader.
 * <p>
 * <strong>IMPLEMENTATION NOTE - The class loader generates source
 * URLs which include the full JAR URL when a class is loaded from a JAR file,
 * which allows setting security permission at the class level, even when a
 * class is contained inside a JAR.
 * <p>
 * <strong>IMPLEMENTATION NOTE - Local repositories are searched in
 * the order they are added via the initial constructor and/or any subsequent
 * calls to <code>addRepository() or addJar().
 * <p>
 * <strong>IMPLEMENTATION NOTE - No check for sealing violations or
 * security is made unless a security manager is present.
 *
 * @author Remy Maucherat
 * @author Craig R. McClanahan
 * @version $Revision: 604974 $ $Date: 2007-12-17 20:36:44 +0100 (lun., 17 déc. 2007) $
 */
public class WebappClassLoader
    extends URLClassLoader
    implements Reloader, Lifecycle
 {

    protected static org.apache.juli.logging.Log log=
        org.apache.juli.logging.LogFactory.getLog( WebappClassLoader.class );

    public static final boolean ENABLE_CLEAR_REFERENCES = 
        Boolean.valueOf(System.getProperty("org.apache.catalina.loader.WebappClassLoader.ENABLE_CLEAR_REFERENCES", "true")).booleanValue();
    
    protected class PrivilegedFindResource
        implements PrivilegedAction {

        protected File file;
        protected String path;

        PrivilegedFindResource(File file, String path) {
            this.file = file;
            this.path = path;
        }

        public Object run() {
            return findResourceInternal(file, path);
        }

    }


    // ------------------------------------------------------- Static Variables


    /**
     * The set of trigger classes that will cause a proposed repository not
     * to be added if this class is visible to the class loader that loaded
     * this factory class.  Typically, trigger classes will be listed for
     * components that have been integrated into the JDK for later versions,
     * but where the corresponding JAR files are required to run on
     * earlier versions.
     */
    protected static final String[] triggers = {
        "javax.servlet.Servlet"                     // Servlet API
    };


    /**
     * Set of package names which are not allowed to be loaded from a webapp
     * class loader without delegating first.
     */
    protected static final String[] packageTriggers = {
    };


    /**
     * The string manager for this package.
     */
    protected static final StringManager sm =
        StringManager.getManager(Constants.Package);

    
    /**
     * Use anti JAR locking code, which does URL rerouting when accessing
     * resources.
     */
    boolean antiJARLocking = false; 
    

    // ----------------------------------------------------------- Constructors


    /**
     * Construct a new ClassLoader with no defined repositories and no
     * parent ClassLoader.
     */
    public WebappClassLoader() {

        super(new URL[0]);
        this.parent = getParent();
        system = getSystemClassLoader();
        securityManager = System.getSecurityManager();

        if (securityManager != null) {
            refreshPolicy();
        }

    }


    /**
     * Construct a new ClassLoader with no defined repositories and no
     * parent ClassLoader.
     */
    public WebappClassLoader(ClassLoader parent) {

        super(new URL[0], parent);
                
        this.parent = getParent();
        
        system = getSystemClassLoader();
        securityManager = System.getSecurityManager();

        if (securityManager != null) {
            refreshPolicy();
        }
    }


    // ----------------------------------------------------- Instance Variables


    /**
     * Associated directory context giving access to the resources in this
     * webapp.
     */
    protected DirContext resources = null;


    /**
     * The cache of ResourceEntry for classes and resources we have loaded,
     * keyed by resource name.
     */
    protected HashMap resourceEntries = new HashMap();


    /**
     * The list of not found resources.
     */
    protected HashMap notFoundResources = new HashMap();


    /**
     * Should this class loader delegate to the parent class loader
     * <strong>before searching its own repositories (i.e. the
     * usual Java2 delegation model)?  If set to <code>false,
     * this class loader will search its own repositories first, and
     * delegate to the parent only if the class or resource is not
     * found locally.
     */
    protected boolean delegate = false;


    /**
     * Last time a JAR was accessed.
     */
    protected long lastJarAccessed = 0L;


    /**
     * The list of local repositories, in the order they should be searched
     * for locally loaded classes or resources.
     */
    protected String[] repositories = new String[0];


     /**
      * Repositories URLs, used to cache the result of getURLs.
      */
     protected URL[] repositoryURLs = null;


    /**
     * Repositories translated as path in the work directory (for Jasper
     * originally), but which is used to generate fake URLs should getURLs be
     * called.
     */
    protected File[] files = new File[0];


    /**
     * The list of JARs, in the order they should be searched
     * for locally loaded classes or resources.
     */
    protected JarFile[] jarFiles = new JarFile[0];


    /**
     * The list of JARs, in the order they should be searched
     * for locally loaded classes or resources.
     */
    protected File[] jarRealFiles = new File[0];


    /**
     * The path which will be monitored for added Jar files.
     */
    protected String jarPath = null;


    /**
     * The list of JARs, in the order they should be searched
     * for locally loaded classes or resources.
     */
    protected String[] jarNames = new String[0];


    /**
     * The list of JARs last modified dates, in the order they should be
     * searched for locally loaded classes or resources.
     */
    protected long[] lastModifiedDates = new long[0];


    /**
     * The list of resources which should be checked when checking for
     * modifications.
     */
    protected String[] paths = new String[0];


    /**
     * A list of read File and Jndi Permission's required if this loader
     * is for a web application context.
     */
    protected ArrayList permissionList = new ArrayList();


    /**
     * Path where resources loaded from JARs will be extracted.
     */
    protected File loaderDir = null;


    /**
     * The PermissionCollection for each CodeSource for a web
     * application context.
     */
    protected HashMap loaderPC = new HashMap();


    /**
     * Instance of the SecurityManager installed.
     */
    protected SecurityManager securityManager = null;


    /**
     * The parent class loader.
     */
    protected ClassLoader parent = null;


    /**
     * The system class loader.
     */
    protected ClassLoader system = null;


    /**
     * Has this component been started?
     */
    protected boolean started = false;


    /**
     * Has external repositories.
     */
    protected boolean hasExternalRepositories = false;

    /**
     * need conversion for properties files
     */
    protected boolean needConvert = false;


    /**
     * All permission.
     */
    protected Permission allPermission = new java.security.AllPermission();


    // ------------------------------------------------------------- Properties


    /**
     * Get associated resources.
     */
    public DirContext getResources() {

        return this.resources;

    }


    /**
     * Set associated resources.
     */
    public void setResources(DirContext resources) {

        this.resources = resources;

    }


    /**
     * Return the "delegate first" flag for this class loader.
     */
    public boolean getDelegate() {

        return (this.delegate);

    }


    /**
     * Set the "delegate first" flag for this class loader.
     *
     * @param delegate The new "delegate first" flag
     */
    public void setDelegate(boolean delegate) {

        this.delegate = delegate;

    }


    /**
     * @return Returns the antiJARLocking.
     */
    public boolean getAntiJARLocking() {
        return antiJARLocking;
    }
    
    
    /**
     * @param antiJARLocking The antiJARLocking to set.
     */
    public void setAntiJARLocking(boolean antiJARLocking) {
        this.antiJARLocking = antiJARLocking;
    }

    
    /**
     * If there is a Java SecurityManager create a read FilePermission
     * or JndiPermission for the file directory path.
     *
     * @param path file directory path
     */
    public void addPermission(String path) {
        if (path == null) {
            return;
        }

        if (securityManager != null) {
            Permission permission = null;
            if( path.startsWith("jndi:") || path.startsWith("jar:jndi:") ) {
                if (!path.endsWith("/")) {
                    path = path + "/";
                }
                permission = new JndiPermission(path + "*");
                addPermission(permission);
            } else {
                if (!path.endsWith(File.separator)) {
                    permission = new FilePermission(path, "read");
                    addPermission(permission);
                    path = path + File.separator;
                }
                permission = new FilePermission(path + "-", "read");
                addPermission(permission);
            }
        }
    }


    /**
     * If there is a Java SecurityManager create a read FilePermission
     * or JndiPermission for URL.
     *
     * @param url URL for a file or directory on local system
     */
    public void addPermission(URL url) {
        if (url != null) {
            addPermission(url.toString());
        }
    }


    /**
     * If there is a Java SecurityManager create a Permission.
     *
     * @param permission The permission
     */
    public void addPermission(Permission permission) {
        if ((securityManager != null) && (permission != null)) {
            permissionList.add(permission);
        }
    }


    /**
     * Return the JAR path.
     */
    public String getJarPath() {

        return this.jarPath;

    }


    /**
     * Change the Jar path.
     */
    public void setJarPath(String jarPath) {

        this.jarPath = jarPath;

    }


    /**
     * Change the work directory.
     */
    public void setWorkDir(File workDir) {
        this.loaderDir = new File(workDir, "loader");
    }

     /**
      * Utility method for use in subclasses.
      * Must be called before Lifecycle methods to have any effect.
      */
     protected void setParentClassLoader(ClassLoader pcl) {
         parent = pcl;
     }

    // ------------------------------------------------------- Reloader Methods


    /**
     * Add a new repository to the set of places this ClassLoader can look for
     * classes to be loaded.
     *
     * @param repository Name of a source of classes to be loaded, such as a
     *  directory pathname, a JAR file pathname, or a ZIP file pathname
     *
     * @exception IllegalArgumentException if the specified repository is
     *  invalid or does not exist
     */
    public void addRepository(String repository) {

        // Ignore any of the standard repositories, as they are set up using
        // either addJar or addRepository
        if (repository.startsWith("/WEB-INF/lib")
            || repository.startsWith("/WEB-INF/classes"))
            return;

        // Add this repository to our underlying class loader
        try {
            URL url = new URL(repository);
            super.addURL(url);
            hasExternalRepositories = true;
            repositoryURLs = null;
        } catch (MalformedURLException e) {
            IllegalArgumentException iae = new IllegalArgumentException
                ("Invalid repository: " + repository); 
            iae.initCause(e);
            throw iae;
        }

    }


    /**
     * Add a new repository to the set of places this ClassLoader can look for
     * classes to be loaded.
     *
     * @param repository Name of a source of classes to be loaded, such as a
     *  directory pathname, a JAR file pathname, or a ZIP file pathname
     *
     * @exception IllegalArgumentException if the specified repository is
     *  invalid or does not exist
     */
    synchronized void addRepository(String repository, File file) {

        // Note : There should be only one (of course), but I think we should
        // keep this a bit generic

        if (repository == null)
            return;

        if (log.isDebugEnabled())
            log.debug("addRepository(" + repository + ")");

        int i;

        // Add this repository to our internal list
        String[] result = new String[repositories.length + 1];
        for (i = 0; i < repositories.length; i++) {
            result[i] = repositories[i];
        }
        result[repositories.length] = repository;
        repositories = result;

        // Add the file to the list
        File[] result2 = new File[files.length + 1];
        for (i = 0; i < files.length; i++) {
            result2[i] = files[i];
        }
        result2[files.length] = file;
        files = result2;

    }


    synchronized void addJar(String jar, JarFile jarFile, File file)
        throws IOException {

        if (jar == null)
            return;
        if (jarFile == null)
            return;
        if (file == null)
            return;

        if (log.isDebugEnabled())
            log.debug("addJar(" + jar + ")");

        int i;

        if ((jarPath != null) && (jar.startsWith(jarPath))) {

            String jarName = jar.substring(jarPath.length());
            while (jarName.startsWith("/"))
                jarName = jarName.substring(1);

            String[] result = new String[jarNames.length + 1];
            for (i = 0; i < jarNames.length; i++) {
                result[i] = jarNames[i];
            }
            result[jarNames.length] = jarName;
            jarNames = result;

        }

        try {

            // Register the JAR for tracking

            long lastModified =
                ((ResourceAttributes) resources.getAttributes(jar))
                .getLastModified();

            String[] result = new String[paths.length + 1];
            for (i = 0; i < paths.length; i++) {
                result[i] = paths[i];
            }
            result[paths.length] = jar;
            paths = result;

            long[] result3 = new long[lastModifiedDates.length + 1];
            for (i = 0; i < lastModifiedDates.length; i++) {
                result3[i] = lastModifiedDates[i];
            }
            result3[lastModifiedDates.length] = lastModified;
            lastModifiedDates = result3;

        } catch (NamingException e) {
            // Ignore
        }

        // If the JAR currently contains invalid classes, don't actually use it
        // for classloading
        if (!validateJarFile(file))
            return;

        JarFile[] result2 = new JarFile[jarFiles.length + 1];
        for (i = 0; i < jarFiles.length; i++) {
            result2[i] = jarFiles[i];
        }
        result2[jarFiles.length] = jarFile;
        jarFiles = result2;

        // Add the file to the list
        File[] result4 = new File[jarRealFiles.length + 1];
        for (i = 0; i < jarRealFiles.length; i++) {
            result4[i] = jarRealFiles[i];
        }
        result4[jarRealFiles.length] = file;
        jarRealFiles = result4;
    }


    /**
     * Return a String array of the current repositories for this class
     * loader.  If there are no repositories, a zero-length array is
     * returned.For security reason, returns a clone of the Array (since 
     * String are immutable).
     */
    public String[] findRepositories() {

        return ((String[])repositories.clone());

    }


    /**
     * Have one or more classes or resources been modified so that a reload
     * is appropriate?
     */
    public boolean modified() {

        if (log.isDebugEnabled())
            log.debug("modified()");

        // Checking for modified loaded resources
        int length = paths.length;

        // A rare race condition can occur in the updates of the two arrays
        // It's totally ok if the latest class added is not checked (it will
        // be checked the next time
        int length2 = lastModifiedDates.length;
        if (length > length2)
            length = length2;

        for (int i = 0; i < length; i++) {
            try {
                long lastModified =
                    ((ResourceAttributes) resources.getAttributes(paths[i]))
                    .getLastModified();
                if (lastModified != lastModifiedDates[i]) {
                    if( log.isDebugEnabled() ) 
                        log.debug("  Resource '" + paths[i]
                                  + "' was modified; Date is now: "
                                  + new java.util.Date(lastModified) + " Was: "
                                  + new java.util.Date(lastModifiedDates[i]));
                    return (true);
                }
            } catch (NamingException e) {
                log.error("    Resource '" + paths[i] + "' is missing");
                return (true);
            }
        }

        length = jarNames.length;

        // Check if JARs have been added or removed
        if (getJarPath() != null) {

            try {
                NamingEnumeration enumeration = resources.listBindings(getJarPath());
                int i = 0;
                while (enumeration.hasMoreElements() && (i < length)) {
                    NameClassPair ncPair = (NameClassPair) enumeration.nextElement();
                    String name = ncPair.getName();
                    // Ignore non JARs present in the lib folder
                    if (!name.endsWith(".jar"))
                        continue;
                    if (!name.equals(jarNames[i])) {
                        // Missing JAR
                        log.info("    Additional JARs have been added : '" 
                                 + name + "'");
                        return (true);
                    }
                    i++;
                }
                if (enumeration.hasMoreElements()) {
                    while (enumeration.hasMoreElements()) {
                        NameClassPair ncPair = 
                            (NameClassPair) enumeration.nextElement();
                        String name = ncPair.getName();
                        // Additional non-JAR files are allowed
                        if (name.endsWith(".jar")) {
                            // There was more JARs
                            log.info("    Additional JARs have been added");
                            return (true);
                        }
                    }
                } else if (i < jarNames.length) {
                    // There was less JARs
                    log.info("    Additional JARs have been added");
                    return (true);
                }
            } catch (NamingException e) {
                if (log.isDebugEnabled())
                    log.debug("    Failed tracking modifications of '"
                        + getJarPath() + "'");
            } catch (ClassCastException e) {
                log.error("    Failed tracking modifications of '"
                          + getJarPath() + "' : " + e.getMessage());
            }

        }

        // No classes have been modified
        return (false);

    }


    /**
     * Render a String representation of this object.
     */
    public String toString() {

        StringBuffer sb = new StringBuffer("WebappClassLoader\r\n");
        sb.append("  delegate: ");
        sb.append(delegate);
        sb.append("\r\n");
        sb.append("  repositories:\r\n");
        if (repositories != null) {
            for (int i = 0; i < repositories.length; i++) {
                sb.append("    ");
                sb.append(repositories[i]);
                sb.append("\r\n");
            }
        }
        if (this.parent != null) {
            sb.append("----------> Parent Classloader:\r\n");
            sb.append(this.parent.toString());
            sb.append("\r\n");
        }
        return (sb.toString());

    }


    // ---------------------------------------------------- ClassLoader Methods


     /**
      * Add the specified URL to the classloader.
      */
     protected void addURL(URL url) {
         super.addURL(url);
         hasExternalRepositories = true;
         repositoryURLs = null;
     }


    /**
     * Find the specified class in our local repositories, if possible.  If
     * not found, throw <code>ClassNotFoundException.
     *
     * @param name Name of the class to be loaded
     *
     * @exception ClassNotFoundException if the class was not found
     */
    public Class findClass(String name) throws ClassNotFoundException {

        if (log.isDebugEnabled())
            log.debug("    findClass(" + name + ")");

        // Cannot load anything from local repositories if class loader is stopped
        if (!started) {
            throw new ClassNotFoundException(name);
        }

        // (1) Permission to define this class when using a SecurityManager
        if (securityManager != null) {
            int i = name.lastIndexOf('.');
            if (i >= 0) {
                try {
                    if (log.isTraceEnabled())
                        log.trace("      securityManager.checkPackageDefinition");
                    securityManager.checkPackageDefinition(name.substring(0,i));
                } catch (Exception se) {
                    if (log.isTraceEnabled())
                        log.trace("      -->Exception-->ClassNotFoundException", se);
                    throw new ClassNotFoundException(name, se);
                }
            }
        }

        // Ask our superclass to locate this class, if possible
        // (throws ClassNotFoundException if it is not found)
        Class clazz = null;
        try {
            if (log.isTraceEnabled())
                log.trace("      findClassInternal(" + name + ")");
            try {
                clazz = findClassInternal(name);
            } catch(ClassNotFoundException cnfe) {
                if (!hasExternalRepositories) {
                    throw cnfe;
                }
            } catch(AccessControlException ace) {
                throw new ClassNotFoundException(name, ace);
            } catch (RuntimeException e) {
                if (log.isTraceEnabled())
                    log.trace("      -->RuntimeException Rethrown", e);
                throw e;
            }
            if ((clazz == null) && hasExternalRepositories) {
                try {
                    synchronized (this) {
                        clazz = super.findClass(name);
                    }
                } catch(AccessControlException ace) {
                    throw new ClassNotFoundException(name, ace);
                } catch (RuntimeException e) {
                    if (log.isTraceEnabled())
                        log.trace("      -->RuntimeException Rethrown", e);
                    throw e;
                }
            }
            if (clazz == null) {
                if (log.isDebugEnabled())
                    log.debug("    --> Returning ClassNotFoundException");
                throw new ClassNotFoundException(name);
            }
        } catch (ClassNotFoundException e) {
            if (log.isTraceEnabled())
                log.trace("    --> Passing on ClassNotFoundException");
            throw e;
        }

        // Return the class we have located
        if (log.isTraceEnabled())
            log.debug("      Returning class " + clazz);
        if ((log.isTraceEnabled()) && (clazz != null))
            log.debug("      Loaded by " + clazz.getClassLoader());
        return (clazz);

    }


    /**
     * Find the specified resource in our local repository, and return a
     * <code>URL refering to it, or null if this resource
     * cannot be found.
     *
     * @param name Name of the resource to be found
     */
    public URL findResource(final String name) {

        if (log.isDebugEnabled())
            log.debug("    findResource(" + name + ")");

        URL url = null;

        ResourceEntry entry = (ResourceEntry) resourceEntries.get(name);
        if (entry == null) {
            entry = findResourceInternal(name, name);
        }
        if (entry != null) {
            url = entry.source;
        }

        if ((url == null) && hasExternalRepositories)
            url = super.findResource(name);

        if (log.isDebugEnabled()) {
            if (url != null)
                log.debug("    --> Returning '" + url.toString() + "'");
            else
                log.debug("    --> Resource not found, returning null");
        }
        return (url);

    }


    /**
     * Return an enumeration of <code>URLs representing all of the
     * resources with the given name.  If no resources with this name are
     * found, return an empty enumeration.
     *
     * @param name Name of the resources to be found
     *
     * @exception IOException if an input/output error occurs
     */
    public Enumeration findResources(String name) throws IOException {

        if (log.isDebugEnabled())
            log.debug("    findResources(" + name + ")");

        Vector result = new Vector();

        int jarFilesLength = jarFiles.length;
        int repositoriesLength = repositories.length;

        int i;

        // Looking at the repositories
        for (i = 0; i < repositoriesLength; i++) {
            try {
                String fullPath = repositories[i] + name;
                resources.lookup(fullPath);
                // Note : Not getting an exception here means the resource was
                // found
                try {
                    result.addElement(getURI(new File(files[i], name)));
                } catch (MalformedURLException e) {
                    // Ignore
                }
            } catch (NamingException e) {
            }
        }

        // Looking at the JAR files
        synchronized (jarFiles) {
            if (openJARs()) {
                for (i = 0; i < jarFilesLength; i++) {
                    JarEntry jarEntry = jarFiles[i].getJarEntry(name);
                    if (jarEntry != null) {
                        try {
                            String jarFakeUrl = getURI(jarRealFiles[i]).toString();
                            jarFakeUrl = "jar:" + jarFakeUrl + "!/" + name;
                            result.addElement(new URL(jarFakeUrl));
                        } catch (MalformedURLException e) {
                            // Ignore
                        }
                    }
                }
            }
        }

        // Adding the results of a call to the superclass
        if (hasExternalRepositories) {

            Enumeration otherResourcePaths = super.findResources(name);

            while (otherResourcePaths.hasMoreElements()) {
                result.addElement(otherResourcePaths.nextElement());
            }

        }

        return result.elements();

    }


    /**
     * Find the resource with the given name.  A resource is some data
     * (images, audio, text, etc.) that can be accessed by class code in a
     * way that is independent of the location of the code.  The name of a
     * resource is a "/"-separated path name that identifies the resource.
     * If the resource cannot be found, return <code>null.
     * <p>
     * This method searches according to the following algorithm, returning
     * as soon as it finds the appropriate URL.  If the resource cannot be
     * found, returns <code>null.
     * <ul>
     * <li>If the delegate property is set to true,
     *     call the <code>getResource() method of the parent class
     *     loader, if any.</li>
     * <li>Call findResource() to find this resource in our
     *     locally defined repositories.</li>
     * <li>Call the getResource() method of the parent class
     *     loader, if any.</li>
     * </ul>
     *
     * @param name Name of the resource to return a URL for
     */
    public URL getResource(String name) {

        if (log.isDebugEnabled())
            log.debug("getResource(" + name + ")");
        URL url = null;

        // (1) Delegate to parent if requested
        if (delegate) {
            if (log.isDebugEnabled())
                log.debug("  Delegating to parent classloader " + parent);
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            url = loader.getResource(name);
            if (url != null) {
                if (log.isDebugEnabled())
                    log.debug("  --> Returning '" + url.toString() + "'");
                return (url);
            }
        }

        // (2) Search local repositories
        url = findResource(name);
        if (url != null) {
            // Locating the repository for special handling in the case 
            // of a JAR
            if (antiJARLocking) {
                ResourceEntry entry = (ResourceEntry) resourceEntries.get(name);
                try {
                    String repository = entry.codeBase.toString();
                    if ((repository.endsWith(".jar")) 
                            && (!(name.endsWith(".class")))) {
                        // Copy binary content to the work directory if not present
                        File resourceFile = new File(loaderDir, name);
                        url = getURI(resourceFile);
                    }
                } catch (Exception e) {
                    // Ignore
                }
            }
            if (log.isDebugEnabled())
                log.debug("  --> Returning '" + url.toString() + "'");
            return (url);
        }

        // (3) Delegate to parent unconditionally if not already attempted
        if( !delegate ) {
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            url = loader.getResource(name);
            if (url != null) {
                if (log.isDebugEnabled())
                    log.debug("  --> Returning '" + url.toString() + "'");
                return (url);
            }
        }

        // (4) Resource was not found
        if (log.isDebugEnabled())
            log.debug("  --> Resource not found, returning null");
        return (null);

    }


    /**
     * Find the resource with the given name, and return an input stream
     * that can be used for reading it.  The search order is as described
     * for <code>getResource(), after checking to see if the resource
     * data has been previously cached.  If the resource cannot be found,
     * return <code>null.
     *
     * @param name Name of the resource to return an input stream for
     */
    public InputStream getResourceAsStream(String name) {

        if (log.isDebugEnabled())
            log.debug("getResourceAsStream(" + name + ")");
        InputStream stream = null;

        // (0) Check for a cached copy of this resource
        stream = findLoadedResource(name);
        if (stream != null) {
            if (log.isDebugEnabled())
                log.debug("  --> Returning stream from cache");
            return (stream);
        }

        // (1) Delegate to parent if requested
        if (delegate) {
            if (log.isDebugEnabled())
                log.debug("  Delegating to parent classloader " + parent);
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            stream = loader.getResourceAsStream(name);
            if (stream != null) {
                // FIXME - cache???
                if (log.isDebugEnabled())
                    log.debug("  --> Returning stream from parent");
                return (stream);
            }
        }

        // (2) Search local repositories
        if (log.isDebugEnabled())
            log.debug("  Searching local repositories");
        URL url = findResource(name);
        if (url != null) {
            // FIXME - cache???
            if (log.isDebugEnabled())
                log.debug("  --> Returning stream from local");
            stream = findLoadedResource(name);
            try {
                if (hasExternalRepositories && (stream == null))
                    stream = url.openStream();
            } catch (IOException e) {
                ; // Ignore
            }
            if (stream != null)
                return (stream);
        }

        // (3) Delegate to parent unconditionally
        if (!delegate) {
            if (log.isDebugEnabled())
                log.debug("  Delegating to parent classloader unconditionally " + parent);
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            stream = loader.getResourceAsStream(name);
            if (stream != null) {
                // FIXME - cache???
                if (log.isDebugEnabled())
                    log.debug("  --> Returning stream from parent");
                return (stream);
            }
        }

        // (4) Resource was not found
        if (log.isDebugEnabled())
            log.debug("  --> Resource not found, returning null");
        return (null);

    }


    /**
     * 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(String name, boolean resolve)
        throws ClassNotFoundException {

        if (log.isDebugEnabled())
            log.debug("loadClass(" + name + ", " + resolve + ")");
        Class clazz = null;

        // Log access to stopped classloader
        if (!started) {
            try {
                throw new IllegalStateException();
            } catch (IllegalStateException e) {
                log.info(sm.getString("webappClassLoader.stopped", name), e);
            }
        }

        // (0) Check our previously loaded local class cache
        clazz = findLoadedClass0(name);
        if (clazz != null) {
            if (log.isDebugEnabled())
                log.debug("  Returning class from cache");
            if (resolve)
                resolveClass(clazz);
            return (clazz);
        }

        // (0.1) Check our previously loaded class cache
        clazz = findLoadedClass(name);
        if (clazz != null) {
            if (log.isDebugEnabled())
                log.debug("  Returning class from cache");
            if (resolve)
                resolveClass(clazz);
            return (clazz);
        }

        // (0.2) Try loading the class with the system class loader, to prevent
        //       the webapp from overriding J2SE classes
        try {
            clazz = system.loadClass(name);
            if (clazz != null) {
                if (resolve)
                    resolveClass(clazz);
                return (clazz);
            }
        } catch (ClassNotFoundException e) {
            // Ignore
        }

        // (0.5) Permission to access this class when using a SecurityManager
        if (securityManager != null) {
            int i = name.lastIndexOf('.');
            if (i >= 0) {
                try {
                    securityManager.checkPackageAccess(name.substring(0,i));
                } catch (SecurityException se) {
                    String error = "Security Violation, attempt to use " +
                        "Restricted Class: " + name;
                    log.info(error, se);
                    throw new ClassNotFoundException(error, se);
                }
            }
        }

        boolean delegateLoad = delegate || filter(name);

        // (1) Delegate to our parent if requested
        if (delegateLoad) {
            if (log.isDebugEnabled())
                log.debug("  Delegating to parent classloader1 " + parent);
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            try {
                clazz = loader.loadClass(name);
                if (clazz != null) {
                    if (log.isDebugEnabled())
                        log.debug("  Loading class from parent");
                    if (resolve)
                        resolveClass(clazz);
                    return (clazz);
                }
            } catch (ClassNotFoundException e) {
                ;
            }
        }

        // (2) Search local repositories
        if (log.isDebugEnabled())
            log.debug("  Searching local repositories");
        try {
            clazz = findClass(name);
            if (clazz != null) {
                if (log.isDebugEnabled())
                    log.debug("  Loading class from local repository");
                if (resolve)
                    resolveClass(clazz);
                return (clazz);
            }
        } catch (ClassNotFoundException e) {
            ;
        }

        // (3) Delegate to parent unconditionally
        if (!delegateLoad) {
            if (log.isDebugEnabled())
                log.debug("  Delegating to parent classloader at end: " + parent);
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            try {
                clazz = loader.loadClass(name);
                if (clazz != null) {
                    if (log.isDebugEnabled())
                        log.debug("  Loading class from parent");
                    if (resolve)
                        resolveClass(clazz);
                    return (clazz);
                }
            } catch (ClassNotFoundException e) {
                ;
            }
        }

        throw new ClassNotFoundException(name);
    }


    /**
     * Get the Permissions for a CodeSource.  If this instance
     * of WebappClassLoader is for a web application context,
     * add read FilePermission or JndiPermissions for the base
     * directory (if unpacked),
     * the context URL, and jar file resources.
     *
     * @param codeSource where the code was loaded from
     * @return PermissionCollection for CodeSource
     */
    protected PermissionCollection getPermissions(CodeSource codeSource) {

        String codeUrl = codeSource.getLocation().toString();
        PermissionCollection pc;
        if ((pc = (PermissionCollection)loaderPC.get(codeUrl)) == null) {
            pc = super.getPermissions(codeSource);
            if (pc != null) {
                Iterator perms = permissionList.iterator();
                while (perms.hasNext()) {
                    Permission p = (Permission)perms.next();
                    pc.add(p);
                }
                loaderPC.put(codeUrl,pc);
            }
        }
        return (pc);

    }


    /**
     * Returns the search path of URLs for loading classes and resources.
     * This includes the original list of URLs specified to the constructor,
     * along with any URLs subsequently appended by the addURL() method.
     * @return the search path of URLs for loading classes and resources.
     */
    public URL[] getURLs() {

        if (repositoryURLs != null) {
            return repositoryURLs;
        }

        URL[] external = super.getURLs();

        int filesLength = files.length;
        int jarFilesLength = jarRealFiles.length;
        int length = filesLength + jarFilesLength + external.length;
        int i;

        try {

            URL[] urls = new URL[length];
            for (i = 0; i < length; i++) {
                if (i < filesLength) {
                    urls[i] = getURL(files[i], true);
                } else if (i < filesLength + jarFilesLength) {
                    urls[i] = getURL(jarRealFiles[i - filesLength], true);
                } else {
                    urls[i] = external[i - filesLength - jarFilesLength];
                }
            }

            repositoryURLs = urls;

        } catch (MalformedURLException e) {
            repositoryURLs = new URL[0];
        }

        return repositoryURLs;

    }


    // ------------------------------------------------------ Lifecycle Methods


    /**
     * Add a lifecycle event listener to this component.
     *
     * @param listener The listener to add
     */
    public void addLifecycleListener(LifecycleListener listener) {
    }


    /**
     * Get the lifecycle listeners associated with this lifecycle. If this 
     * Lifecycle has no listeners registered, a zero-length array is returned.
     */
    public LifecycleListener[] findLifecycleListeners() {
        return new LifecycleListener[0];
    }


    /**
     * Remove a lifecycle event listener from this component.
     *
     * @param listener The listener to remove
     */
    public void removeLifecycleListener(LifecycleListener listener) {
    }


    /**
     * Start the class loader.
     *
     * @exception LifecycleException if a lifecycle error occurs
     */
    public void start() throws LifecycleException {

        started = true;
        String encoding = null;
        try {
            encoding = System.getProperty("file.encoding");
        } catch (Exception e) {
            return;
        }
        if (encoding.indexOf("EBCDIC")!=-1) {
            needConvert = true;
        }

    }


    /**
     * Stop the class loader.
     *
     * @exception LifecycleException if a lifecycle error occurs
     */
    public void stop() throws LifecycleException {

        // Clearing references should be done before setting started to
        // false, due to possible side effects
        clearReferences();

        started = false;

        int length = files.length;
        for (int i = 0; i < length; i++) {
            files[i] = null;
        }

        length = jarFiles.length;
        for (int i = 0; i < length; i++) {
            try {
                if (jarFiles[i] != null) {
                    jarFiles[i].close();
                }
            } catch (IOException e) {
                // Ignore
            }
            jarFiles[i] = null;
        }

        notFoundResources.clear();
        resourceEntries.clear();
        resources = null;
        repositories = null;
        repositoryURLs = null;
        files = null;
        jarFiles = null;
        jarRealFiles = null;
        jarPath = null;
        jarNames = null;
        lastModifiedDates = null;
        paths = null;
        hasExternalRepositories = false;
        parent = null;

        permissionList.clear();
        loaderPC.clear();

        if (loaderDir != null) {
            deleteDir(loaderDir);
        }

    }


    /**
     * Used to periodically signal to the classloader to release 
     * JAR resources.
     */
    public void closeJARs(boolean force) {
        if (jarFiles.length > 0) {
                synchronized (jarFiles) {
                    if (force || (System.currentTimeMillis() 
                                  > (lastJarAccessed + 90000))) {
                        for (int i = 0; i < jarFiles.length; i++) {
                            try {
                                if (jarFiles[i] != null) {
                                    jarFiles[i].close();
                                    jarFiles[i] = null;
                                }
                            } catch (IOException e) {
                                if (log.isDebugEnabled()) {
                                    log.debug("Failed to close JAR", e);
                                }
                            }
                        }
                    }
                }
        }
    }


    // ------------------------------------------------------ Protected Methods

    
    /**
     * Clear references.
     */
    protected void clearReferences() {

        // Unregister any JDBC drivers loaded by this classloader
        Enumeration drivers = DriverManager.getDrivers();
        while (drivers.hasMoreElements()) {
            Driver driver = (Driver) drivers.nextElement();
            if (driver.getClass().getClassLoader() == this) {
                try {
                    DriverManager.deregisterDriver(driver);
                } catch (SQLException e) {
                    log.warn("SQL driver deregistration failed", e);
                }
            }
        }
        
        // Null out any static or final fields from loaded classes,
        // as a workaround for apparent garbage collection bugs
        if (ENABLE_CLEAR_REFERENCES) {
            Iterator loadedClasses = ((HashMap) resourceEntries.clone()).values().iterator();
            while (loadedClasses.hasNext()) {
                ResourceEntry entry = (ResourceEntry) loadedClasses.next();
                if (entry.loadedClass != null) {
                    Class clazz = entry.loadedClass;
                    try {
                        Field[] fields = clazz.getDeclaredFields();
                        for (int i = 0; i < fields.length; i++) {
                            Field field = fields[i];
                            int mods = field.getModifiers();
                            if (field.getType().isPrimitive() 
                                    || (field.getName().indexOf("$") != -1)) {
                                continue;
                            }
                            if (Modifier.isStatic(mods)) {
                                try {
                                    field.setAccessible(true);
                                    if (Modifier.isFinal(mods)) {
                                        if (!((field.getType().getName().startsWith("java."))
                                                || (field.getType().getName().startsWith("javax.")))) {
                                            nullInstance(field.get(null));
                                        }
                                    } else {
                                        field.set(null, null);
                                        if (log.isDebugEnabled()) {
                                            log.debug("Set field " + field.getName() 
                                                    + " to null in class " + clazz.getName());
                                        }
                                    }
                                } catch (Throwable t) {
                                    if (log.isDebugEnabled()) {
                                        log.debug("Could not set field " + field.getName() 
                                                + " to null in class " + clazz.getName(), t);
                                    }
                                }
                            }
                        }
                    } catch (Throwable t) {
                        if (log.isDebugEnabled()) {
                            log.debug("Could not clean fields for class " + clazz.getName(), t);
                        }
                    }
                }
            }
        }
        
         // Clear the IntrospectionUtils cache.
        IntrospectionUtils.clear();
        
        // Clear the classloader reference in common-logging
        org.apache.juli.logging.LogFactory.release(this);
        
        // Clear the classloader reference in the VM's bean introspector
        java.beans.Introspector.flushCaches();

    }


    protected void nullInstance(Object instance) {
        if (instance == null) {
            return;
        }
        Field[] fields = instance.getClass().getDeclaredFields();
        for (int i = 0; i < fields.length; i++) {
            Field field = fields[i];
            int mods = field.getModifiers();
            if (field.getType().isPrimitive() 
                    || (field.getName().indexOf("$") != -1)) {
                continue;
            }
            try {
                field.setAccessible(true);
                if (Modifier.isStatic(mods) && Modifier.isFinal(mods)) {
                    // Doing something recursively is too risky
                    continue;
                } else {
                    Object value = field.get(instance);
                    if (null != value) {
                        Class valueClass = value.getClass();
                        if (!loadedByThisOrChild(valueClass)) {
                            if (log.isDebugEnabled()) {
                                log.debug("Not setting field " + field.getName() +
                                        " to null in object of class " + 
                                        instance.getClass().getName() +
                                        " because the referenced object was of type " +
                                        valueClass.getName() + 
                                        " which was not loaded by this WebappClassLoader.");
                            }
                        } else {
                            field.set(instance, null);
                            if (log.isDebugEnabled()) {
                                log.debug("Set field " + field.getName() 
                                        + " to null in class " + instance.getClass().getName());
                            }
                        }
                    }
                }
            } catch (Throwable t) {
                if (log.isDebugEnabled()) {
                    log.debug("Could not set field " + field.getName() 
                            + " to null in object instance of class " 
                            + instance.getClass().getName(), t);
                }
            }
        }
    }


    /**
     * Determine whether a class was loaded by this class loader or one of
     * its child class loaders.
     */
    protected boolean loadedByThisOrChild(Class clazz)
    {
        boolean result = false;
        for (ClassLoader classLoader = clazz.getClassLoader();
                null != classLoader; classLoader = classLoader.getParent()) {
            if (classLoader.equals(this)) {
                result = true;
                break;
            }
        }
        return result;
    }    


    /**
     * Used to periodically signal to the classloader to release JAR resources.
     */
    protected boolean openJARs() {
        if (started && (jarFiles.length > 0)) {
            lastJarAccessed = System.currentTimeMillis();
            if (jarFiles[0] == null) {
                for (int i = 0; i < jarFiles.length; i++) {
                    try {
                        jarFiles[i] = new JarFile(jarRealFiles[i]);
                    } catch (IOException e) {
                        if (log.isDebugEnabled()) {
                            log.debug("Failed to open JAR", e);
                        }
                        return false;
                    }
                }
            }
        }
        return true;
    }


    /**
     * Find specified class in local repositories.
     *
     * @return the loaded class, or null if the class isn't found
     */
    protected Class findClassInternal(String name)
        throws ClassNotFoundException {

        if (!validate(name))
            throw new ClassNotFoundException(name);

        String tempPath = name.replace('.', '/');
        String classPath = tempPath + ".class";

        ResourceEntry entry = null;

        entry = findResourceInternal(name, classPath);

        if (entry == null)
            throw new ClassNotFoundException(name);

        Class clazz = entry.loadedClass;
        if (clazz != null)
            return clazz;

        synchronized (this) {
            if (entry.binaryContent == null && entry.loadedClass == null)
                throw new ClassNotFoundException(name);

            // Looking up the package
            String packageName = null;
            int pos = name.lastIndexOf('.');
            if (pos != -1)
                packageName = name.substring(0, pos);
        
            Package pkg = null;
        
            if (packageName != null) {
                pkg = getPackage(packageName);
                // Define the package (if null)
                if (pkg == null) {
                    try {
                        if (entry.manifest == null) {
                            definePackage(packageName, null, null, null, null,
                                    null, null, null);
                        } else {
                            definePackage(packageName, entry.manifest,
                                    entry.codeBase);
                        }
                    } catch (IllegalArgumentException e) {
                        // Ignore: normal error due to dual definition of package
                    }
                    pkg = getPackage(packageName);
                }
            }
    
            if (securityManager != null) {

                // Checking sealing
                if (pkg != null) {
                    boolean sealCheck = true;
                    if (pkg.isSealed()) {
                        sealCheck = pkg.isSealed(entry.codeBase);
                    } else {
                        sealCheck = (entry.manifest == null)
                            || !isPackageSealed(packageName, entry.manifest);
                    }
                    if (!sealCheck)
                        throw new SecurityException
                            ("Sealing violation loading " + name + " : Package "
                             + packageName + " is sealed.");
                }
    
            }

            if (entry.loadedClass == null) {
                clazz = defineClass(name, entry.binaryContent, 0,
                        entry.binaryContent.length, 
                        new CodeSource(entry.codeBase, entry.certificates));
                entry.loadedClass = clazz;
                entry.binaryContent = null;
                entry.source = null;
                entry.codeBase = null;
                entry.manifest = null;
                entry.certificates = null;
            } else {
                clazz = entry.loadedClass;
            }
        }
        
        return clazz;

    }

    /**
     * Find specified resource in local repositories. This block
     * will execute under an AccessControl.doPrivilege block.
     *
     * @return the loaded resource, or null if the resource isn't found
     */
    protected ResourceEntry findResourceInternal(File file, String path){
        ResourceEntry entry = new ResourceEntry();
        try {
            entry.source = getURI(new File(file, path));
            entry.codeBase = getURL(new File(file, path), false);
        } catch (MalformedURLException e) {
            return null;
        }   
        return entry;
    }
    

    /**
     * Find specified resource in local repositories.
     *
     * @return the loaded resource, or null if the resource isn't found
     */
    protected ResourceEntry findResourceInternal(String name, String path) {

        if (!started) {
            log.info(sm.getString("webappClassLoader.stopped", name));
            return null;
        }

        if ((name == null) || (path == null))
            return null;

        ResourceEntry entry = (ResourceEntry) resourceEntries.get(name);
        if (entry != null)
            return entry;

        int contentLength = -1;
        InputStream binaryStream = null;

        int jarFilesLength = jarFiles.length;
        int repositoriesLength = repositories.length;

        int i;

        Resource resource = null;

        boolean fileNeedConvert = false;

        for (i = 0; (entry == null) && (i < repositoriesLength); i++) {
            try {

                String fullPath = repositories[i] + path;

                Object lookupResult = resources.lookup(fullPath);
                if (lookupResult instanceof Resource) {
                    resource = (Resource) lookupResult;
                }

                // Note : Not getting an exception here means the resource was
                // found
                 if (securityManager != null) {
                    PrivilegedAction dp =
                        new PrivilegedFindResource(files[i], path);
                    entry = (ResourceEntry)AccessController.doPrivileged(dp);
                 } else {
                    entry = findResourceInternal(files[i], path);
                 }

                ResourceAttributes attributes =
                    (ResourceAttributes) resources.getAttributes(fullPath);
                contentLength = (int) attributes.getContentLength();
                entry.lastModified = attributes.getLastModified();

                if (resource != null) {


                    try {
                        binaryStream = resource.streamContent();
                    } catch (IOException e) {
                        return null;
                    }

                    if (needConvert) {
                        if (path.endsWith(".properties")) {
                            fileNeedConvert = true;
                        }
                    }

                    // Register the full path for modification checking
                    // Note: Only syncing on a 'constant' object is needed
                    synchronized (allPermission) {

                        int j;

                        long[] result2 = 
                            new long[lastModifiedDates.length + 1];
                        for (j = 0; j < lastModifiedDates.length; j++) {
                            result2[j] = lastModifiedDates[j];
                        }
                        result2[lastModifiedDates.length] = entry.lastModified;
                        lastModifiedDates = result2;

                        String[] result = new String[paths.length + 1];
                        for (j = 0; j < paths.length; j++) {
                            result[j] = paths[j];
                        }
                        result[paths.length] = fullPath;
                        paths = result;

                    }

                }

            } catch (NamingException e) {
            }
        }

        if ((entry == null) && (notFoundResources.containsKey(name)))
            return null;

        JarEntry jarEntry = null;

        synchronized (jarFiles) {

            if (!openJARs()) {
                return null;
            }
            for (i = 0; (entry == null) && (i < jarFilesLength); i++) {

                jarEntry = jarFiles[i].getJarEntry(path);

                if (jarEntry != null) {

                    entry = new ResourceEntry();
                    try {
                        entry.codeBase = getURL(jarRealFiles[i], false);
                        String jarFakeUrl = getURI(jarRealFiles[i]).toString();
                        jarFakeUrl = "jar:" + jarFakeUrl + "!/" + path;
                        entry.source = new URL(jarFakeUrl);
                        entry.lastModified = jarRealFiles[i].lastModified();
                    } catch (MalformedURLException e) {
                        return null;
                    }
                    contentLength = (int) jarEntry.getSize();
                    try {
                        entry.manifest = jarFiles[i].getManifest();
                        binaryStream = jarFiles[i].getInputStream(jarEntry);
                    } catch (IOException e) {
                        return null;
                    }

                    // Extract resources contained in JAR to the workdir
                    if (antiJARLocking && !(path.endsWith(".class"))) {
                        byte[] buf = new byte[1024];
                        File resourceFile = new File
                            (loaderDir, jarEntry.getName());
                        if (!resourceFile.exists()) {
                            Enumeration entries = jarFiles[i].entries();
                            while (entries.hasMoreElements()) {
                                JarEntry jarEntry2 = 
                                    (JarEntry) entries.nextElement();
                                if (!(jarEntry2.isDirectory()) 
                                    && (!jarEntry2.getName().endsWith
                                        (".class"))) {
                                    resourceFile = new File
                                        (loaderDir, jarEntry2.getName());
                                    resourceFile.getParentFile().mkdirs();
                                    FileOutputStream os = null;
                                    InputStream is = null;
                                    try {
                                        is = jarFiles[i].getInputStream
                                            (jarEntry2);
                                        os = new FileOutputStream
                                            (resourceFile);
                                        while (true) {
                                            int n = is.read(buf);
                                            if (n <= 0) {
                                                break;
                                            }
                                            os.write(buf, 0, n);
                                        }
                                    } catch (IOException e) {
                                        // Ignore
                                    } finally {
                                        try {
                                            if (is != null) {
                                                is.close();
                                            }
                                        } catch (IOException e) {
                                        }
                                        try {
                                            if (os != null) {
                                                os.close();
                                            }
                                        } catch (IOException e) {
                                        }
                                    }
                                }
                            }
                        }
                    }

                }

            }

            if (entry == null) {
                synchronized (notFoundResources) {
                    notFoundResources.put(name, name);
                }
                return null;
            }

            if (binaryStream != null) {

                byte[] binaryContent = new byte[contentLength];

                int pos = 0;
                try {

                    while (true) {
                        int n = binaryStream.read(binaryContent, pos,
                                                  binaryContent.length - pos);
                        if (n <= 0)
                            break;
                        pos += n;
                    }
                    binaryStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                    return null;
                } catch (Exception e) {
                    e.printStackTrace();
                    return null;
                }

                if (fileNeedConvert) {
                    String str = new String(binaryContent,0,pos);
                    try {
                        binaryContent = str.getBytes("UTF-8");
                    } catch (Exception e) {
                        return null;
                    }
                }
                entry.binaryContent = binaryContent;

                // The certificates are only available after the JarEntry 
                // associated input stream has been fully read
                if (jarEntry != null) {
                    entry.certificates = jarEntry.getCertificates();
                }

            }

        }

        // Add the entry in the local resource repository
        synchronized (resourceEntries) {
            // Ensures that all the threads which may be in a race to load
            // a particular class all end up with the same ResourceEntry
            // instance
            ResourceEntry entry2 = (ResourceEntry) resourceEntries.get(name);
            if (entry2 == null) {
                resourceEntries.put(name, entry);
            } else {
                entry = entry2;
            }
        }

        return entry;

    }


    /**
     * Returns true if the specified package name is sealed according to the
     * given manifest.
     */
    protected boolean isPackageSealed(String name, Manifest man) {

        String path = name.replace('.', '/') + '/';
        Attributes attr = man.getAttributes(path); 
        String sealed = null;
        if (attr != null) {
            sealed = attr.getValue(Name.SEALED);
        }
        if (sealed == null) {
            if ((attr = man.getMainAttributes()) != null) {
                sealed = attr.getValue(Name.SEALED);
            }
        }
        return "true".equalsIgnoreCase(sealed);

    }


    /**
     * Finds the resource with the given name if it has previously been
     * loaded and cached by this class loader, and return an input stream
     * to the resource data.  If this resource has not been cached, return
     * <code>null.
     *
     * @param name Name of the resource to return
     */
    protected InputStream findLoadedResource(String name) {

        ResourceEntry entry = (ResourceEntry) resourceEntries.get(name);
        if (entry != null) {
            if (entry.binaryContent != null)
                return new ByteArrayInputStream(entry.binaryContent);
        }
        return (null);

    }


    /**
     * Finds the class with the given name if it has previously been
     * loaded and cached by this class loader, and return the Class object.
     * If this class has not been cached, return <code>null.
     *
     * @param name Name of the resource to return
     */
    protected Class findLoadedClass0(String name) {

        ResourceEntry entry = (ResourceEntry) resourceEntries.get(name);
        if (entry != null) {
            return entry.loadedClass;
        }
        return (null);  // FIXME - findLoadedResource()

    }


    /**
     * Refresh the system policy file, to pick up eventual changes.
     */
    protected void refreshPolicy() {

        try {
            // The policy file may have been modified to adjust 
            // permissions, so we're reloading it when loading or 
            // reloading a Context
            Policy policy = Policy.getPolicy();
            policy.refresh();
        } catch (AccessControlException e) {
            // Some policy files may restrict this, even for the core,
            // so this exception is ignored
        }

    }


    /**
     * Filter classes.
     * 
     * @param name class name
     * @return true if the class should be filtered
     */
    protected boolean filter(String name) {

        if (name == null)
            return false;

        // Looking up the package
        String packageName = null;
        int pos = name.lastIndexOf('.');
        if (pos != -1)
            packageName = name.substring(0, pos);
        else
            return false;

        for (int i = 0; i < packageTriggers.length; i++) {
            if (packageName.startsWith(packageTriggers[i]))
                return true;
        }

        return false;

    }


    /**
     * Validate a classname. As per SRV.9.7.2, we must restict loading of 
     * classes from J2SE (java.*) and classes of the servlet API 
     * (javax.servlet.*). That should enhance robustness and prevent a number
     * of user error (where an older version of servlet.jar would be present
     * in /WEB-INF/lib).
     * 
     * @param name class name
     * @return true if the name is valid
     */
    protected boolean validate(String name) {

        if (name == null)
            return false;
        if (name.startsWith("java."))
            return false;

        return true;

    }


    /**
     * Check the specified JAR file, and return <code>true if it does
     * not contain any of the trigger classes.
     *
     * @param jarfile The JAR file to be checked
     *
     * @exception IOException if an input/output error occurs
     */
    protected boolean validateJarFile(File jarfile)
        throws IOException {

        if (triggers == null)
            return (true);
        JarFile jarFile = new JarFile(jarfile);
        for (int i = 0; i < triggers.length; i++) {
            Class clazz = null;
            try {
                if (parent != null) {
                    clazz = parent.loadClass(triggers[i]);
                } else {
                    clazz = Class.forName(triggers[i]);
                }
            } catch (Throwable t) {
                clazz = null;
            }
            if (clazz == null)
                continue;
            String name = triggers[i].replace('.', '/') + ".class";
            if (log.isDebugEnabled())
                log.debug(" Checking for " + name);
            JarEntry jarEntry = jarFile.getJarEntry(name);
            if (jarEntry != null) {
                log.info("validateJarFile(" + jarfile + 
                    ") - jar not loaded. See Servlet Spec 2.3, "
                    + "section 9.7.2. Offending class: " + name);
                jarFile.close();
                return (false);
            }
        }
        jarFile.close();
        return (true);

    }


    /**
     * Get URL.
     */
    protected URL getURL(File file, boolean encoded)
        throws MalformedURLException {

        File realFile = file;
        try {
            realFile = realFile.getCanonicalFile();
        } catch (IOException e) {
            // Ignore
        }
        if(encoded) {
            return getURI(realFile);
        } else {
            return realFile.toURL();
        }

    }


    /**
     * Get URL.
     */
    protected URL getURI(File file)
        throws MalformedURLException {


        File realFile = file;
        try {
            realFile = realFile.getCanonicalFile();
        } catch (IOException e) {
            // Ignore
        }
        return realFile.toURI().toURL();

    }


    /**
     * Delete the specified directory, including all of its contents and
     * subdirectories recursively.
     *
     * @param dir File object representing the directory to be deleted
     */
    protected static void deleteDir(File dir) {

        String files[] = dir.list();
        if (files == null) {
            files = new String[0];
        }
        for (int i = 0; i < files.length; i++) {
            File file = new File(dir, files[i]);
            if (file.isDirectory()) {
                deleteDir(file);
            } else {
                file.delete();
            }
        }
        dir.delete();

    }


}

Other Tomcat examples (source code examples)

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

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