diff --git a/src/main/org/apache/tools/ant/AntClassLoader.java b/src/main/org/apache/tools/ant/AntClassLoader.java
index e7bc33d8c..0eb41fa11 100644
--- a/src/main/org/apache/tools/ant/AntClassLoader.java
+++ b/src/main/org/apache/tools/ant/AntClassLoader.java
@@ -1,7 +1,7 @@
 /*
  * The Apache Software License, Version 1.1
  *
- * Copyright (c) 1999 The Apache Software Foundation.  All rights
+ * Copyright (c) 2000-2001 The Apache Software Foundation.  All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -54,6 +54,7 @@
 
 package org.apache.tools.ant;
 
+import java.lang.reflect.*;
 import java.util.*;
 import java.util.zip.*;
 import java.io.*;
@@ -65,7 +66,8 @@ import org.apache.tools.ant.types.Path;
  * system classpath by using the forceLoadClass method. Any subsequent classes loaded by that
  * class will then use this loader rather than the system class loader.
  *
- * @author Conor MacNeill
+ * @author <a href="mailto:conor@cortexebusiness.com.au">Conor MacNeill</a>
+ * @author <a href="mailto:Jesse.Glick@netbeans.com">Jesse Glick</a>
  */
 public class AntClassLoader  extends ClassLoader {
     /**
@@ -101,6 +103,19 @@ public class AntClassLoader  extends ClassLoader {
      */
     private Vector loaderPackages = new Vector();
     
+    private static Method getProtectionDomain = null;
+    private static Method defineClassProtectionDomain = null;
+    static {
+        try {
+            getProtectionDomain = Class.class.getMethod("getProtectionDomain", new Class[0]);
+            Class protectionDomain = Class.forName("java.security.ProtectionDomain");
+            Class[] args = new Class[] {String.class, byte[].class, Integer.TYPE, Integer.TYPE, protectionDomain};
+            defineClassProtectionDomain = ClassLoader.class.getDeclaredMethod("defineClass", args);
+        }
+        catch (Exception e) {}
+    }
+
+
     /**
      * Create a classloader for the given project using the classpath given.
      *
@@ -198,7 +213,7 @@ public class AntClassLoader  extends ClassLoader {
         Class theClass = findLoadedClass(classname);
 
         if (theClass == null) {
-            theClass = findSystemClass(classname);
+            theClass = findBaseClass(classname);
         }
         
         return theClass;
@@ -325,7 +340,7 @@ public class AntClassLoader  extends ClassLoader {
         if (theClass == null) {
             if (useSystemFirst) {
                 try {
-                    theClass = findSystemClass(classname);
+                    theClass = findBaseClass(classname);
                     project.log("Class " + classname + " loaded from system loader", Project.MSG_DEBUG);
                 }
                 catch (ClassNotFoundException cnfe) {
@@ -339,7 +354,7 @@ public class AntClassLoader  extends ClassLoader {
                     project.log("Class " + classname + " loaded from ant loader", Project.MSG_DEBUG);
                 }
                 catch (ClassNotFoundException cnfe) {
-                    theClass = findSystemClass(classname);
+                    theClass = findBaseClass(classname);
                     project.log("Class " + classname + " loaded from system loader", Project.MSG_DEBUG);
                 }
             }
@@ -387,10 +402,33 @@ public class AntClassLoader  extends ClassLoader {
         
         byte[] classData = baos.toByteArray();
 
-        return defineClass(classname, classData, 0, classData.length); 
+        // Simply put:
+        // defineClass(classname, classData, 0, classData.length, Project.class.getProtectionDomain());
+        // Made more elaborate to be 1.1-safe.
+        if (defineClassProtectionDomain != null) {
+            try {
+                Object domain = getProtectionDomain.invoke(Project.class, new Object[0]);
+                Object[] args = new Object[] {classname, classData, new Integer(0), new Integer(classData.length), domain};
+                return (Class)defineClassProtectionDomain.invoke(this, args);
+            }
+            catch (InvocationTargetException ite) {
+                Throwable t = ite.getTargetException();
+                if (t instanceof ClassFormatError) {
+                    throw (ClassFormatError)t;
+                }
+                else {
+                    throw new IOException(t.toString());
+                }
+            }
+            catch (Exception e) {
+                throw new IOException(e.toString());
+            }
+        }
+        else {
+            return defineClass(classname, classData, 0, classData.length); 
+        }
     }
 
-
     /**
      * Search for and load a class on the classpath of this class loader.
      *
@@ -447,4 +485,17 @@ public class AntClassLoader  extends ClassLoader {
             catch (IOException e) {}
         }
     }
+
+    /**
+     * Find a system class (which should be loaded from the same classloader as the Ant core).
+     */
+    private Class findBaseClass(String name) throws ClassNotFoundException {
+        ClassLoader base = AntClassLoader.class.getClassLoader();
+        if (base == null) {
+            return findSystemClass(name);
+        }
+        else {
+            return base.loadClass(name);
+        }
+    }
 }