001 /*
002 * This file is part of the Jikes RVM project (http://jikesrvm.org).
003 *
004 * This file is licensed to You under the Eclipse Public License (EPL);
005 * You may not use this file except in compliance with the License. You
006 * may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/eclipse-1.0.php
009 *
010 * See the COPYRIGHT.txt file distributed with this work for information
011 * regarding copyright ownership.
012 */
013 package org.jikesrvm.classloader;
014
015 import java.io.File;
016 import java.net.MalformedURLException;
017 import java.net.URL;
018 import java.net.URLClassLoader;
019 import java.util.StringTokenizer;
020 import org.jikesrvm.VM;
021 import org.jikesrvm.runtime.Magic;
022
023 /**
024 * The class loader used by Jikes RVM to load the application program. Since
025 * version 1.2 of the Sun API docs, the Application ClassLoader and the
026 * System Class Loader are officially the same thing. (What Jikes RVM used to
027 * call the "System Class Loader" is officially the "Bootstrap Class
028 * Loader".)
029 * <p>
030 * We use a two-link chain. An ordinary user's class is loaded by this class
031 * loader. This class loader first delegates to its parent (the Bootstrap
032 * Class Loader) before trying the class itself.
033 * <p>
034 * Renamed the former "system class loader" to the "bootstrap class loader".
035 */
036 public class ApplicationClassLoader extends URLClassLoader {
037
038 static final boolean DBG = false;
039
040 static int numInstantiations = 0;
041
042 /** For status printing, to make sure that, if an application class loader is
043 * created at boot image writing time, it won't leak out into the next
044 * mode. This is actually not used any more, but it should never hurt,
045 * and can give one a sense of confidence when debugging Jikes RVM's
046 * classloaders.
047 * */
048 private final boolean createdAtBootImageWritingTime;
049 private final boolean createdWithRunningVM;
050
051 public ApplicationClassLoader(String specifiedClasspath) {
052 super(new URL[0]);
053 if (DBG) {
054 VM.sysWriteln("The Application Class Loader has been instantiated ", numInstantiations, " times");
055 }
056 ++numInstantiations;
057
058 createdAtBootImageWritingTime = VM.writingBootImage;
059 createdWithRunningVM = VM.runningVM;
060
061 try {
062 if (specifiedClasspath == null) {
063 addURL(new URL("file", null, -1, System.getProperty("user.dir") + File.separator));
064 } else {
065 StringTokenizer tok = new StringTokenizer(specifiedClasspath, File.pathSeparator);
066 while (tok.hasMoreElements()) {
067 String elt = tok.nextToken();
068
069 if (!(elt.endsWith(".jar") || elt.endsWith(".zip"))) {
070 if (!elt.endsWith(File.separator)) {
071 elt += File.separator;
072 }
073 }
074
075 if (elt.indexOf(File.pathSeparatorChar) != -1) {
076 addURL(new URL(elt));
077 } else if (elt.startsWith(File.separator)) {
078 addURL(new URL("file", null, -1, elt));
079 } else {
080 addURL(new URL("file", null, -1, System.getProperty("user.dir") + File.separator + elt));
081 }
082 }
083 }
084 } catch (MalformedURLException e) {
085 VM.sysFail(
086 "JikesRVM: ApplicationClassLoader: Initialization Failed with a MalformedURLException; there was an error setting the application's classpath: " +
087 e);
088 }
089 }
090
091 /** Name of the Application Class Loader. Actually used by Jikes RVM's
092 * serialization code.
093 * <P>
094 * I intended this name to reflect both "SystemClassLoader" and
095 * "ApplicationClassLoader".
096 */
097 public static final String myName = "SystemAppCL";
098
099 @Override
100 public String toString() {
101 return myName +
102 (createdAtBootImageWritingTime ? "-createdAtBootImageWritingTime" : "") +
103 (createdWithRunningVM ? "" : "-NOTcreatedWithRunningVM") +
104 (DBG ? "@" + VM.addressAsHexString(Magic.objectAsAddress(this)) : "");
105 }
106
107 @Override
108 protected String findLibrary(String libName) {
109 return null;
110 }
111 }
112
113