/*
 * Copyright (c) 1995, 2013, 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 sun.applet;

import java.lang.NullPointerException;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.SocketPermission;
import java.net.URLConnection;
import java.net.MalformedURLException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.io.EOFException;
import java.io.File;
import java.io.FilePermission;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.NoSuchElementException;
import java.security.AccessController;
import java.security.AccessControlContext;
import java.security.PrivilegedAction;
import java.security.PrivilegedExceptionAction;
import java.security.PrivilegedActionException;
import java.security.CodeSource;
import java.security.Permission;
import java.security.PermissionCollection;
import sun.awt.AppContext;
import sun.awt.SunToolkit;
import sun.misc.IOUtils;
import sun.net.www.ParseUtil;
import sun.security.util.SecurityConstants;

This class defines the class loader for loading applet classes and
resources. It extends URLClassLoader to search the applet code base
for the class or resource after checking any loaded JAR files.
/**
 * This class defines the class loader for loading applet classes and
 * resources. It extends URLClassLoader to search the applet code base
 * for the class or resource after checking any loaded JAR files.
 */
public class AppletClassLoader extends URLClassLoader {
    private URL base;   /* applet code base URL */
    private CodeSource codesource; /* codesource for the base URL */
    private AccessControlContext acc;
    private boolean exceptionStatus = false;

    private final Object threadGroupSynchronizer = new Object();
    private final Object grabReleaseSynchronizer = new Object();

    private boolean codebaseLookup = true;
    private volatile boolean allowRecursiveDirectoryRead = true;

    /*
     * Creates a new AppletClassLoader for the specified base URL.
     */
    protected AppletClassLoader(URL base) {
        super(new URL[0]);
        this.base = base;
        this.codesource =
            new CodeSource(base, (java.security.cert.Certificate[]) null);
        acc = AccessController.getContext();
    }

    public void disableRecursiveDirectoryRead() {
        allowRecursiveDirectoryRead = false;
    }


    
Set the codebase lookup flag.
/**
     * Set the codebase lookup flag.
     */
    void setCodebaseLookup(boolean codebaseLookup)  {
        this.codebaseLookup = codebaseLookup;
    }

    /*
     * Returns the applet code base URL.
     */
    URL getBaseURL() {
        return base;
    }

    /*
     * Returns the URLs used for loading classes and resources.
     */
    public URL[] getURLs() {
        URL[] jars = super.getURLs();
        URL[] urls = new URL[jars.length + 1];
        System.arraycopy(jars, 0, urls, 0, jars.length);
        urls[urls.length - 1] = base;
        return urls;
    }

    /*
     * Adds the specified JAR file to the search path of loaded JAR files.
     * Changed modifier to protected in order to be able to overwrite addJar()
     * in PluginClassLoader.java
     */
    protected void addJar(String name) throws IOException {
        URL url;
        try {
            url = new URL(base, name);
        } catch (MalformedURLException e) {
            throw new IllegalArgumentException("name");
        }
        addURL(url);
        // DEBUG
        //URL[] urls = getURLs();
        //for (int i = 0; i < urls.length; i++) {
        //    System.out.println("url[" + i + "] = " + urls[i]);
        //}
    }

    /*
     * Override loadClass so that class loading errors can be caught in
     * order to print better error messages.
     */
    public synchronized Class loadClass(String name, boolean resolve)
        throws ClassNotFoundException
    {
        // First check if we have permission to access the package. This
        // should go away once we've added support for exported packages.
        int i = name.lastIndexOf('.');
        if (i != -1) {
            SecurityManager sm = System.getSecurityManager();
            if (sm != null)
                sm.checkPackageAccess(name.substring(0, i));
        }
        try {
            return super.loadClass(name, resolve);
        } catch (ClassNotFoundException e) {
            //printError(name, e.getException());
            throw e;
        } catch (RuntimeException e) {
            //printError(name, e);
            throw e;
        } catch (Error e) {
            //printError(name, e);
            throw e;
        }
    }

    /*
     * Finds the applet class with the specified name. First searches
     * loaded JAR files then the applet code base for the class.
     */
    protected Class findClass(String name) throws ClassNotFoundException {

        int index = name.indexOf(";");
        String cookie = "";
        if(index != -1) {
                cookie = name.substring(index, name.length());
                name = name.substring(0, index);
        }

        // check loaded JAR files
        try {
            return super.findClass(name);
        } catch (ClassNotFoundException e) {
        }

        // Otherwise, try loading the class from the code base URL

        // 4668479: Option to turn off codebase lookup in AppletClassLoader
        // during resource requests. [stanley.ho]
        if (codebaseLookup == false)
            throw new ClassNotFoundException(name);

//      final String path = name.replace('.', '/').concat(".class").concat(cookie);
        String encodedName = ParseUtil.encodePath(name.replace('.', '/'), false);
        final String path = (new StringBuffer(encodedName)).append(".class").append(cookie).toString();
        try {
            byte[] b = (byte[]) AccessController.doPrivileged(
                               new PrivilegedExceptionAction() {
                public Object run() throws IOException {
                   try {
                        URL finalURL = new URL(base, path);

                        // Make sure the codebase won't be modified
                        if (base.getProtocol().equals(finalURL.getProtocol()) &&
                            base.getHost().equals(finalURL.getHost()) &&
                            base.getPort() == finalURL.getPort()) {
                            return getBytes(finalURL);
                        }
                        else {
                            return null;
                        }
                    } catch (Exception e) {
                        return null;
                    }
                }
            }, acc);

            if (b != null) {
                return defineClass(name, b, 0, b.length, codesource);
            } else {
                throw new ClassNotFoundException(name);
            }
        } catch (PrivilegedActionException e) {
            throw new ClassNotFoundException(name, e.getException());
        }
    }

    
Returns the permissions for the given codesource object.
The implementation of this method first calls super.getPermissions,
to get the permissions
granted by the super class, and then adds additional permissions
based on the URL of the codesource.

If the protocol is "file"
and the path specifies a file, permission is granted to read all files
and (recursively) all files and subdirectories contained in
that directory. This is so applets with a codebase of
file:/blah/some.jar can read in file:/blah/, which is needed to
be backward compatible. We also add permission to connect back to
the "localhost".
Params:
codesource – the codesource
Throws:
NullPointerException – if codesource is null.
Returns:
the permissions granted to the codesource/**
     * Returns the permissions for the given codesource object.
     * The implementation of this method first calls super.getPermissions,
     * to get the permissions
     * granted by the super class, and then adds additional permissions
     * based on the URL of the codesource.
     * <p>
     * If the protocol is "file"
     * and the path specifies a file, permission is granted to read all files
     * and (recursively) all files and subdirectories contained in
     * that directory. This is so applets with a codebase of
     * file:/blah/some.jar can read in file:/blah/, which is needed to
     * be backward compatible. We also add permission to connect back to
     * the "localhost".
     *
     * @param codesource the codesource
     * @throws NullPointerException if {@code codesource} is {@code null}.
     * @return the permissions granted to the codesource
     */
    protected PermissionCollection getPermissions(CodeSource codesource)
    {
        final PermissionCollection perms = super.getPermissions(codesource);

        URL url = codesource.getLocation();

        String path = null;
        Permission p;

        try {
            p = url.openConnection().getPermission();
        } catch (java.io.IOException ioe) {
            p = null;
        }

        if (p instanceof FilePermission) {
            path = p.getName();
        } else if ((p == null) && (url.getProtocol().equals("file"))) {
            path = url.getFile().replace('/', File.separatorChar);
            path = ParseUtil.decode(path);
        }

        if (path != null) {
            final String rawPath = path;
            if (!path.endsWith(File.separator)) {
                int endIndex = path.lastIndexOf(File.separatorChar);
                if (endIndex != -1) {
                        path = path.substring(0, endIndex + 1) + "-";
                        perms.add(new FilePermission(path,
                            SecurityConstants.FILE_READ_ACTION));
                }
            }
            final File f = new File(rawPath);
            final boolean isDirectory = f.isDirectory();
            // grant codebase recursive read permission
            // this should only be granted to non-UNC file URL codebase and
            // the codesource path must either be a directory, or a file
            // that ends with .jar or .zip
            if (allowRecursiveDirectoryRead && (isDirectory ||
                    rawPath.toLowerCase().endsWith(".jar") ||
                    rawPath.toLowerCase().endsWith(".zip"))) {

            Permission bperm;
                try {
                    bperm = base.openConnection().getPermission();
                } catch (java.io.IOException ioe) {
                    bperm = null;
                }
                if (bperm instanceof FilePermission) {
                    String bpath = bperm.getName();
                    if (bpath.endsWith(File.separator)) {
                        bpath += "-";
                    }
                    perms.add(new FilePermission(bpath,
                        SecurityConstants.FILE_READ_ACTION));
                } else if ((bperm == null) && (base.getProtocol().equals("file"))) {
                    String bpath = base.getFile().replace('/', File.separatorChar);
                    bpath = ParseUtil.decode(bpath);
                    if (bpath.endsWith(File.separator)) {
                        bpath += "-";
                    }
                    perms.add(new FilePermission(bpath, SecurityConstants.FILE_READ_ACTION));
                }

            }
        }
        return perms;
    }

    /*
     * Returns the contents of the specified URL as an array of bytes.
     */
    private static byte[] getBytes(URL url) throws IOException {
        URLConnection uc = url.openConnection();
        if (uc instanceof java.net.HttpURLConnection) {
            java.net.HttpURLConnection huc = (java.net.HttpURLConnection) uc;
            int code = huc.getResponseCode();
            if (code >= java.net.HttpURLConnection.HTTP_BAD_REQUEST) {
                throw new IOException("open HTTP connection failed.");
            }
        }
        int len = uc.getContentLength();

        // Fixed #4507227: Slow performance to load
        // class and resources. [stanleyh]
        //
        // Use buffered input stream [stanleyh]
        InputStream in = new BufferedInputStream(uc.getInputStream());

        byte[] b;
        try {
            b = IOUtils.readAllBytes(in);
            if (len != -1 && b.length != len)
                throw new EOFException("Expected:" + len + ", read:" + b.length);
        } finally {
            in.close();
        }
        return b;
    }

    // Object for synchronization around getResourceAsStream()
    private Object syncResourceAsStream = new Object();
    private Object syncResourceAsStreamFromJar = new Object();

    // Flag to indicate getResourceAsStream() is in call
    private boolean resourceAsStreamInCall = false;
    private boolean resourceAsStreamFromJarInCall = false;

    
Returns an input stream for reading the specified resource. The search order is described in the documentation for ClassLoader.getResource(String).

Params:
name – the resource name
Returns:
an input stream for reading the resource, or null
        if the resource could not be found
Since:
 JDK1.1/**
     * Returns an input stream for reading the specified resource.
     *
     * The search order is described in the documentation for {@link
     * #getResource(String)}.<p>
     *
     * @param  name the resource name
     * @return an input stream for reading the resource, or <code>null</code>
     *         if the resource could not be found
     * @since  JDK1.1
     */
    public InputStream getResourceAsStream(String name)
    {

        if (name == null) {
            throw new NullPointerException("name");
        }

        try
        {
            InputStream is = null;

            // Fixed #4507227: Slow performance to load
            // class and resources. [stanleyh]
            //
            // The following is used to avoid calling
            // AppletClassLoader.findResource() in
            // super.getResourceAsStream(). Otherwise,
            // unnecessary connection will be made.
            //
            synchronized(syncResourceAsStream)
            {
                resourceAsStreamInCall = true;

                // Call super class
                is = super.getResourceAsStream(name);

                resourceAsStreamInCall = false;
            }

            // 4668479: Option to turn off codebase lookup in AppletClassLoader
            // during resource requests. [stanley.ho]
            if (codebaseLookup == true && is == null)
            {
                // If resource cannot be obtained,
                // try to download it from codebase
                URL url = new URL(base, ParseUtil.encodePath(name, false));
                is = url.openStream();
            }

            return is;
        }
        catch (Exception e)
        {
            return null;
        }
    }


    
Returns an input stream for reading the specified resource from the the loaded jar files. The search order is described in the documentation for ClassLoader.getResource(String).

Params:
name – the resource name
Returns:
an input stream for reading the resource, or null
        if the resource could not be found
Since:
 JDK1.1/**
     * Returns an input stream for reading the specified resource from the
     * the loaded jar files.
     *
     * The search order is described in the documentation for {@link
     * #getResource(String)}.<p>
     *
     * @param  name the resource name
     * @return an input stream for reading the resource, or <code>null</code>
     *         if the resource could not be found
     * @since  JDK1.1
     */
    public InputStream getResourceAsStreamFromJar(String name) {

        if (name == null) {
            throw new NullPointerException("name");
        }

        try {
            InputStream is = null;
            synchronized(syncResourceAsStreamFromJar) {
                resourceAsStreamFromJarInCall = true;
                // Call super class
                is = super.getResourceAsStream(name);
                resourceAsStreamFromJarInCall = false;
            }

            return is;
        } catch (Exception e) {
            return null;
        }
    }


    /*
     * Finds the applet resource with the specified name. First checks
     * loaded JAR files then the applet code base for the resource.
     */
    public URL findResource(String name) {
        // check loaded JAR files
        URL url = super.findResource(name);

        // 6215746:  Disable META-INF/* lookup from codebase in
        // applet/plugin classloader. [stanley.ho]
        if (name.startsWith("META-INF/"))
            return url;

        // 4668479: Option to turn off codebase lookup in AppletClassLoader
        // during resource requests. [stanley.ho]
        if (codebaseLookup == false)
            return url;

        if (url == null)
        {
            //#4805170, if it is a call from Applet.getImage()
            //we should check for the image only in the archives
            boolean insideGetResourceAsStreamFromJar = false;
                synchronized(syncResourceAsStreamFromJar) {
                insideGetResourceAsStreamFromJar = resourceAsStreamFromJarInCall;
            }

            if (insideGetResourceAsStreamFromJar) {
                return null;
            }

            // Fixed #4507227: Slow performance to load
            // class and resources. [stanleyh]
            //
            // Check if getResourceAsStream is called.
            //
            boolean insideGetResourceAsStream = false;

            synchronized(syncResourceAsStream)
            {
                insideGetResourceAsStream = resourceAsStreamInCall;
            }

            // If getResourceAsStream is called, don't
            // trigger the following code. Otherwise,
            // unnecessary connection will be made.
            //
            if (insideGetResourceAsStream == false)
            {
                // otherwise, try the code base
                try {
                    url = new URL(base, ParseUtil.encodePath(name, false));
                    // check if resource exists
                    if(!resourceExists(url))
                        url = null;
                } catch (Exception e) {
                    // all exceptions, including security exceptions, are caught
                    url = null;
                }
            }
        }
        return url;
    }


    private boolean resourceExists(URL url) {
        // Check if the resource exists.
        // It almost works to just try to do an openConnection() but
        // HttpURLConnection will return true on HTTP_BAD_REQUEST
        // when the requested name ends in ".html", ".htm", and ".txt"
        // and we want to be able to handle these
        //
        // Also, cannot just open a connection for things like FileURLConnection,
        // because they succeed when connecting to a nonexistent file.
        // So, in those cases we open and close an input stream.
        boolean ok = true;
        try {
            URLConnection conn = url.openConnection();
            if (conn instanceof java.net.HttpURLConnection) {
                java.net.HttpURLConnection hconn =
                    (java.net.HttpURLConnection) conn;

                // To reduce overhead, using http HEAD method instead of GET method
                hconn.setRequestMethod("HEAD");

                int code = hconn.getResponseCode();
                if (code == java.net.HttpURLConnection.HTTP_OK) {
                    return true;
                }
                if (code >= java.net.HttpURLConnection.HTTP_BAD_REQUEST) {
                    return false;
                }
            } else {
                /**
                 * Fix for #4182052 - stanleyh
                 *
                 * The same connection should be reused to avoid multiple
                 * HTTP connections
                 */

                // our best guess for the other cases
                InputStream is = conn.getInputStream();
                is.close();
            }
        } catch (Exception ex) {
            ok = false;
        }
        return ok;
    }

    /*
     * Returns an enumeration of all the applet resources with the specified
     * name. First checks loaded JAR files then the applet code base for all
     * available resources.
     */
    public Enumeration findResources(String name) throws IOException {

        final Enumeration e = super.findResources(name);

        // 6215746:  Disable META-INF/* lookup from codebase in
        // applet/plugin classloader. [stanley.ho]
        if (name.startsWith("META-INF/"))
            return e;

        // 4668479: Option to turn off codebase lookup in AppletClassLoader
        // during resource requests. [stanley.ho]
        if (codebaseLookup == false)
            return e;

        URL u = new URL(base, ParseUtil.encodePath(name, false));
        if (!resourceExists(u)) {
            u = null;
        }

        final URL url = u;
        return new Enumeration() {
            private boolean done;
            public Object nextElement() {
                if (!done) {
                    if (e.hasMoreElements()) {
                        return e.nextElement();
                    }
                    done = true;
                    if (url != null) {
                        return url;
                    }
                }
                throw new NoSuchElementException();
            }
            public boolean hasMoreElements() {
                return !done && (e.hasMoreElements() || url != null);
            }
        };
    }

    /*
     * Load and resolve the file specified by the applet tag CODE
     * attribute. The argument can either be the relative path
     * of the class file itself or just the name of the class.
     */
    Class loadCode(String name) throws ClassNotFoundException {
        // first convert any '/' or native file separator to .
        name = name.replace('/', '.');
        name = name.replace(File.separatorChar, '.');

        // deal with URL rewriting
        String cookie = null;
        int index = name.indexOf(";");
        if(index != -1) {
                cookie = name.substring(index, name.length());
                name = name.substring(0, index);
        }

        // save that name for later
        String fullName = name;
        // then strip off any suffixes
        if (name.endsWith(".class") || name.endsWith(".java")) {
            name = name.substring(0, name.lastIndexOf('.'));
        }
        try {
                if(cookie != null)
                        name = (new StringBuffer(name)).append(cookie).toString();
            return loadClass(name);
        } catch (ClassNotFoundException e) {
        }
        // then if it didn't end with .java or .class, or in the
        // really pathological case of a class named class or java
        if(cookie != null)
                fullName = (new StringBuffer(fullName)).append(cookie).toString();

        return loadClass(fullName);
    }

    /*
     * The threadgroup that the applets loaded by this classloader live
     * in. In the sun.* implementation of applets, the security manager's
     * (AppletSecurity) getThreadGroup returns the thread group of the
     * first applet on the stack, which is the applet's thread group.
     */
    private AppletThreadGroup threadGroup;
    private AppContext appContext;

    public ThreadGroup getThreadGroup() {
      synchronized (threadGroupSynchronizer) {
        if (threadGroup == null || threadGroup.isDestroyed()) {
            AccessController.doPrivileged(new PrivilegedAction() {
                public Object run() {
                    threadGroup = new AppletThreadGroup(base + "-threadGroup");
                    // threadGroup.setDaemon(true);
                    // threadGroup is now destroyed by AppContext.dispose()

                    // Create the new AppContext from within a Thread belonging
                    // to the newly created ThreadGroup, and wait for the
                    // creation to complete before returning from this method.
                    AppContextCreator creatorThread = new AppContextCreator(threadGroup);

                    // Since this thread will later be used to launch the
                    // applet's AWT-event dispatch thread and we want the applet
                    // code executing the AWT callbacks to use their own class
                    // loader rather than the system class loader, explicitly
                    // set the context class loader to the AppletClassLoader.
                    creatorThread.setContextClassLoader(AppletClassLoader.this);

                    creatorThread.start();
                    try {
                        synchronized(creatorThread.syncObject) {
                            while (!creatorThread.created) {
                                creatorThread.syncObject.wait();
                            }
                        }
                    } catch (InterruptedException e) { }
                    appContext = creatorThread.appContext;
                    return null;
                }
            });
        }
        return threadGroup;
      }
    }

    /*
     * Get the AppContext, if any, corresponding to this AppletClassLoader.
     */
    public AppContext getAppContext()  {
        return appContext;
    }

    int usageCount = 0;

    
Grab this AppletClassLoader and its ThreadGroup/AppContext, so they
won't be destroyed.
/**
     * Grab this AppletClassLoader and its ThreadGroup/AppContext, so they
     * won't be destroyed.
     */
public     void grab() {
        synchronized(grabReleaseSynchronizer) {
            usageCount++;
        }
        getThreadGroup(); // Make sure ThreadGroup/AppContext exist
    }

    protected void setExceptionStatus()
    {
        exceptionStatus = true;
    }

    public boolean getExceptionStatus()
    {
        return exceptionStatus;
    }

    
Release this AppletClassLoader and its ThreadGroup/AppContext.
If nothing else has grabbed this AppletClassLoader, its ThreadGroup
and AppContext will be destroyed.
Because this method may destroy the AppletClassLoader's ThreadGroup,
this method should NOT be called from within the AppletClassLoader's
ThreadGroup.
Changed modifier to protected in order to be able to overwrite this
function in PluginClassLoader.java
/**
     * Release this AppletClassLoader and its ThreadGroup/AppContext.
     * If nothing else has grabbed this AppletClassLoader, its ThreadGroup
     * and AppContext will be destroyed.
     *
     * Because this method may destroy the AppletClassLoader's ThreadGroup,
     * this method should NOT be called from within the AppletClassLoader's
     * ThreadGroup.
     *
     * Changed modifier to protected in order to be able to overwrite this
     * function in PluginClassLoader.java
     */
    protected void release() {

        AppContext tempAppContext = null;

        synchronized(grabReleaseSynchronizer) {
            if (usageCount > 1)  {
                --usageCount;
            } else {
                synchronized(threadGroupSynchronizer) {
                    tempAppContext = resetAppContext();
                }
            }
        }

        // Dispose appContext outside any sync block to
        // prevent potential deadlock.
        if (tempAppContext != null)  {
            try {
                tempAppContext.dispose(); // nuke the world!
            } catch (IllegalThreadStateException e) { }
        }
    }

    /*
     * reset classloader's AppContext and ThreadGroup
     * This method is for subclass PluginClassLoader to
     * reset superclass's AppContext and ThreadGroup but do
     * not dispose the AppContext. PluginClassLoader does not
     * use UsageCount to decide whether to dispose AppContext
     *
     * @return previous AppContext
     */
    protected AppContext resetAppContext() {
        AppContext tempAppContext = null;

        synchronized(threadGroupSynchronizer) {
            // Store app context in temp variable
            tempAppContext = appContext;
            usageCount = 0;
            appContext = null;
            threadGroup = null;
        }
        return tempAppContext;
    }


    // Hash map to store applet compatibility info
    private HashMap jdk11AppletInfo = new HashMap();
    private HashMap jdk12AppletInfo = new HashMap();

    
Set applet target level as JDK 1.1.
Params:
clazz – Applet class.
bool – true if JDK is targeted for JDK 1.1;
            false otherwise./**
     * Set applet target level as JDK 1.1.
     *
     * @param clazz Applet class.
     * @param bool true if JDK is targeted for JDK 1.1;
     *             false otherwise.
     */
    void setJDK11Target(Class clazz, boolean bool)
    {
         jdk11AppletInfo.put(clazz.toString(), Boolean.valueOf(bool));
    }

    
Set applet target level as JDK 1.2.
Params:
clazz – Applet class.
bool – true if JDK is targeted for JDK 1.2;
            false otherwise./**
     * Set applet target level as JDK 1.2.
     *
     * @param clazz Applet class.
     * @param bool true if JDK is targeted for JDK 1.2;
     *             false otherwise.
     */
    void setJDK12Target(Class clazz, boolean bool)
    {
        jdk12AppletInfo.put(clazz.toString(), Boolean.valueOf(bool));
    }

    
Determine if applet is targeted for JDK 1.1.
Params:
applet – Applet class.
Returns:
TRUE if applet is targeted for JDK 1.1;
        FALSE if applet is not;
        null if applet is unknown./**
     * Determine if applet is targeted for JDK 1.1.
     *
     * @param applet Applet class.
     * @return TRUE if applet is targeted for JDK 1.1;
     *         FALSE if applet is not;
     *         null if applet is unknown.
     */
    Boolean isJDK11Target(Class clazz)
    {
        return (Boolean) jdk11AppletInfo.get(clazz.toString());
    }

    
Determine if applet is targeted for JDK 1.2.
Params:
applet – Applet class.
Returns:
TRUE if applet is targeted for JDK 1.2;
        FALSE if applet is not;
        null if applet is unknown./**
     * Determine if applet is targeted for JDK 1.2.
     *
     * @param applet Applet class.
     * @return TRUE if applet is targeted for JDK 1.2;
     *         FALSE if applet is not;
     *         null if applet is unknown.
     */
    Boolean isJDK12Target(Class clazz)
    {
        return (Boolean) jdk12AppletInfo.get(clazz.toString());
    }

    private static AppletMessageHandler mh =
        new AppletMessageHandler("appletclassloader");

    /*
     * Prints a class loading error message.
     */
    private static void printError(String name, Throwable e) {
        String s = null;
        if (e == null) {
            s = mh.getMessage("filenotfound", name);
        } else if (e instanceof IOException) {
            s = mh.getMessage("fileioexception", name);
        } else if (e instanceof ClassFormatError) {
            s = mh.getMessage("fileformat", name);
        } else if (e instanceof ThreadDeath) {
            s = mh.getMessage("filedeath", name);
        } else if (e instanceof Error) {
            s = mh.getMessage("fileerror", e.toString(), name);
        }
        if (s != null) {
            System.err.println(s);
        }
    }
}

/*
 * The AppContextCreator class is used to create an AppContext from within
 * a Thread belonging to the new AppContext's ThreadGroup.  To wait for
 * this operation to complete before continuing, wait for the notifyAll()
 * operation on the syncObject to occur.
 */
class AppContextCreator extends Thread  {
    Object syncObject = new Object();
    AppContext appContext = null;
    volatile boolean created = false;

    AppContextCreator(ThreadGroup group)  {
        super(group, "AppContextCreator");
    }

    public void run()  {
        appContext = SunToolkit.createNewAppContext();
        created = true;
        synchronized(syncObject) {
            syncObject.notifyAll();
        }
    } // run()

} // class AppContextCreator