--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/classes/java/lang/ClassLoader.java	Fri Jan 23 10:14:01 2015 -0800
@@ -0,0 +1,257 @@
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is licensed 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 java.lang;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.nio.ByteBuffer;
+import java.security.ProtectionDomain;
+import java.util.Enumeration;
+import java.util.Vector;
+
+import sun.misc.CompoundEnumeration;
+
+/**
+ * @author Nastaran Shafiei <nastaran.shafiei@gmail.com>
+ * 
+ *  Model class for java.lang.ClassLoader
+ */
+public abstract class ClassLoader {
+  
+  private ClassLoader parent;
+
+  // This is JPF internal identifier which set to the globalId of the classLoader
+  private int nativeId;
+
+  //--- internals
+
+  protected ClassLoader() {
+    // constructed on the native side
+  }
+
+  protected ClassLoader (ClassLoader parent){
+    // constructed on the native side
+  }
+
+  private native String getResource0 (String rname);
+
+  public URL getResource(String name) {
+    URL url = null;
+
+    if(parent == null) {
+      String resourcePath = getSystemClassLoader().getResource0(name);
+      try {
+        url = new URL(resourcePath);
+      } catch (MalformedURLException x){
+        url = null;
+      }
+    } else {
+      url = parent.getResource(name);
+    }
+
+    if (url == null) {
+      url = findResource(name);
+    }
+    return url;
+  }
+
+  /**
+   * Finds the resource with the given name. Class loader implementations
+   * should override this method to specify where to find resources.
+   */
+  protected URL findResource(String name) {
+      return null;
+  }
+
+  private native String[] getResources0 (String rname);
+
+  /**
+   * Returns an array of URL including all resources with the given name 
+   * found in the classpath of this classloader.
+   */
+  private Enumeration<URL> getResourcesURL(String name) {
+    String[] urls = getResources0(name);
+    Vector<URL> list = new Vector<URL>(0);
+    for(String url: urls) {
+      try {
+        list.add(new URL(url));
+      } catch (MalformedURLException x){
+        // process the rest
+      }
+    }
+
+    return list.elements();
+  }
+
+  @SuppressWarnings({"unchecked","rawtypes"})
+  public Enumeration<URL> getResources(String name) throws IOException {
+    Enumeration<URL>[] resEnum = new Enumeration[2];
+
+    if(parent == null) {
+      resEnum[0] = getSystemClassLoader().getResourcesURL(name);
+    } else{
+      resEnum[0] = parent.getResources(name);
+    }
+    resEnum[1] = findResources(name);
+
+    return new CompoundEnumeration<URL>(resEnum);
+  }
+
+  /**
+   * Returns an enumeration representing all the resources with the given 
+   * name. Class loader implementations should override this method to 
+   * specify where to load resources from.
+   */
+  protected Enumeration<URL> findResources(String name) throws IOException {
+      return (new Vector<URL>()).elements();
+  }
+
+  public InputStream getResourceAsStream (String name){
+    URL foundResource = getResource(name);
+    if (foundResource != null) {
+      try {
+        return foundResource.openStream();
+      } catch (IOException e) {
+        System.err.println("cannot open resource " + name);
+      }
+    }
+    return null;
+  }
+
+  public native static ClassLoader getSystemClassLoader ();
+
+  public static URL getSystemResource(String name){
+    return getSystemClassLoader().getResource(name);
+  }
+
+  public static InputStream getSystemResourceAsStream(String name) {
+    return getSystemClassLoader().getResourceAsStream(name);
+  }
+
+  public static Enumeration<URL> getSystemResources(String name) throws IOException {
+    return getSystemClassLoader().getResources(name);
+  }
+
+  public ClassLoader getParent() {
+    return parent;
+  }
+
+  /**
+   * If the class with the given name has been already defined, it is returned. OW, it
+   * returns null.
+   */
+  protected native final Class<?> findLoadedClass(String name);
+
+  protected native final Class<?> findSystemClass(String name) throws ClassNotFoundException;
+
+  public Class<?> loadClass(String name) throws ClassNotFoundException {
+    Class<?> c = findLoadedClass(name);
+
+    if(c == null) {
+      try {
+        if (parent != null && parent != getSystemClassLoader()) {
+          c = parent.loadClass(name, false);
+        } else {
+          c = findSystemClass(name);
+        }
+      } catch (ClassNotFoundException e) {
+        c = findClass(name);
+      }
+    }
+
+    return c;
+  }
+
+  protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
+    return loadClass(name);
+  }
+
+  /**
+   * Finds the class with a given name. This method should be overridden by 
+   * ClassLoader subclasses, and it will be used by loadClass().
+   */
+  protected Class<?> findClass(String name) throws ClassNotFoundException {
+      throw new ClassNotFoundException(name);
+  }
+
+  /**
+   * All the class objects are resolved internally by JPF. So this method
+   * does nothing.
+   */
+  protected final void resolveClass(Class<?> c) {
+  }
+
+  private native Class<?> defineClass0(String name, byte[] b, int off, int len);
+
+  protected final Class<?> defineClass(String name, byte[] b, int off, int len) throws ClassFormatError {
+    return defineClass0(name, b, off, len);
+  }
+
+  protected final Class<?> defineClass(String name, byte[] b, int off, int len, ProtectionDomain protectionDomain) throws ClassFormatError {
+    return defineClass(name, b, off, len);
+  }
+
+  protected String findLibrary(String libname) {
+    return null;
+  }
+
+  protected native Package getPackage(String name);
+
+  protected native Package[] getPackages();
+
+  public native void setDefaultAssertionStatus(boolean enabled);
+
+  public native void setClassAssertionStatus(String className, boolean enabled);
+
+  public native void setPackageAssertionStatus(String packageName, boolean enabled);
+
+  public native void clearAssertionStatus();
+
+  //--- unsupported methods
+
+  protected static boolean registerAsParallelCapable() {
+    return true; // dummy, in prep for jdk7
+  }
+
+  protected Object getClassLoadingLock(String className) {
+    throw new UnsupportedOperationException();
+  }
+
+  protected final Class<?> defineClass(byte[] b, int off, int len) 
+      throws ClassFormatError {
+    throw new UnsupportedOperationException();
+  }
+
+  protected final Class<?> defineClass(String name, ByteBuffer b, ProtectionDomain protectionDomain) 
+      throws ClassFormatError {
+    throw new UnsupportedOperationException();
+  }
+
+  protected final void setSigners(Class<?> c, Object[] signers) {
+    throw new UnsupportedOperationException();
+  }
+
+  protected Package definePackage(String name, String specTitle, String specVersion, 
+                                  String specVendor, String implTitle, String implVersion,
+                                  String implVendor, URL sealBase) 
+                                      throws IllegalArgumentException {
+    throw new UnsupportedOperationException();
+  }
+}