Index: src/main/org/apache/tools/ant/IntrospectionHelper.java
===================================================================
RCS file: /home/cvspublic/ant/src/main/org/apache/tools/ant/IntrospectionHelper.java,v
retrieving revision 1.85
diff -u -r1.85 IntrospectionHelper.java
--- src/main/org/apache/tools/ant/IntrospectionHelper.java	12 Jun 2004 16:51:09 -0000	1.85
+++ src/main/org/apache/tools/ant/IntrospectionHelper.java	22 Jul 2004 22:36:07 -0000
@@ -18,6 +18,8 @@
 package org.apache.tools.ant;
 
 import java.io.File;
+import java.lang.ref.Reference;
+import java.lang.ref.WeakReference;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -26,6 +28,8 @@
 import java.util.Hashtable;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
+import java.util.WeakHashMap;
 import org.apache.tools.ant.types.EnumeratedAttribute;
 import org.apache.tools.ant.taskdefs.PreSetDef;
 
@@ -78,9 +82,9 @@
     private Class bean;
 
     /**
-     * Helper instances we've already created (Class to IntrospectionHelper).
+     * Helper instances we've already created for particular classes.
      */
-    private static Hashtable helpers = new Hashtable();
+    private static Map/*<Class,Reference<IntrospectionHelper>>*/ helpers = new WeakHashMap();
 
     /**
      * Map from primitive types to wrapper classes for use in
@@ -432,12 +436,7 @@
      * @return a helper for the specified class
      */
     public static synchronized IntrospectionHelper getHelper(Class c) {
-        IntrospectionHelper ih = (IntrospectionHelper) helpers.get(c);
-        if (ih == null) {
-            ih = new IntrospectionHelper(c);
-            helpers.put(c, ih);
-        }
-        return ih;
+        return getHelper(null, c);
     }
 
     /**
@@ -455,12 +454,15 @@
      */
     public static synchronized IntrospectionHelper getHelper(Project p, 
                                                              Class c) {
-        IntrospectionHelper ih = (IntrospectionHelper) helpers.get(c);
+        Reference/*<IntrospectionHelper>*/ r = (Reference) helpers.get(c);
+        IntrospectionHelper ih = r != null ? (IntrospectionHelper) r.get() : null;
         if (ih == null) {
             ih = new IntrospectionHelper(c);
-            helpers.put(c, ih);
-            // Cleanup at end of project
-            p.addBuildListener(ih);
+            helpers.put(c, new WeakReference(ih));
+            if (p != null) {
+                // Cleanup at end of project
+                p.addBuildListener(ih);
+            }
         }
         return ih;
     }