--- src/main/org/apache/tools/ant/AntClassLoader.java	(revision 446566)
+++ src/main/org/apache/tools/ant/AntClassLoader.java	(working copy)
@@ -261,7 +261,7 @@ 
      *                elements are set up to start with.
      */
     public AntClassLoader(Project project, Path classpath) {
-        setParent(null);
+        setParent(project.getCoreLoader());
         setProject(project);
         setClassPath(classpath);
     }
@@ -307,7 +307,7 @@ 
      */
     public AntClassLoader(Project project, Path classpath,
                           boolean parentFirst) {
-        this(null, project, classpath, parentFirst);
+        this(project.getCoreLoader(), project, classpath, parentFirst);
     }
 
     /**
--- src/main/org/apache/tools/ant/ComponentHelper.java	(revision 446566)
+++ src/main/org/apache/tools/ant/ComponentHelper.java	(working copy)
@@ -264,6 +264,22 @@ 
     }
 
     /**
+     * Reset the classloaders for those types that have
+     * not yet been instaniated.
+     */
+    protected void resetCoreLoader(
+        ClassLoader oldLoader, ClassLoader newLoader) {
+        for (Iterator i = antTypeTable.values().iterator(); i.hasNext();) {
+            AntTypeDefinition def = (AntTypeDefinition) i.next();
+            Class clazz = def.getClazz();
+            ClassLoader loader = def.getClassLoader();
+            if (clazz == null && (loader == oldLoader)) {
+                def.setClassLoader(newLoader);
+            }
+        }
+    }
+    
+    /**
      * This method is initialization code implementing the original ant component
      * loading from /org/apache/tools/ant/taskdefs/default.properties
      * and /org/apache/tools/ant/types/default.properties.
--- src/main/org/apache/tools/ant/Project.java	(revision 446566)
+++ src/main/org/apache/tools/ant/Project.java	(working copy)
@@ -163,10 +163,10 @@ 
     private Vector listeners = new Vector();
 
     /**
-     * The Ant core classloader--may be <code>null</code> if using
-     * parent classloader.
+     * The Ant core classloader.
+     * This is used for loading in tasks and types.
      */
-    private ClassLoader coreLoader = null;
+    private ClassLoader coreLoader = Project.class.getClassLoader();
 
     /** Records the latest task to be executed on a thread. */
     private Map/*<Thread,Task>*/ threadTasks = Collections.synchronizedMap(new WeakHashMap());
@@ -316,7 +316,7 @@ 
      */
     public AntClassLoader createClassLoader(Path path) {
         return new AntClassLoader(
-            getClass().getClassLoader(), this, path);
+            getCoreLoader(), this, path);
     }
 
     /**
@@ -337,11 +337,27 @@ 
      * Set the core classloader for the project. If a <code>null</code>
      * classloader is specified, the parent classloader should be used.
      *
+     * The coreLoader *must* be able to loader *this* Project class.
      * @param coreLoader The classloader to use for the project.
      *                   May be <code>null</code>.
      */
     public void setCoreLoader(ClassLoader coreLoader) {
+        if (coreLoader == null) {
+            coreLoader = getClass().getClassLoader();
+        }
+        try {
+            Class cl = coreLoader.loadClass(getClass().getName());
+            if (cl != getClass()) {
+                throw new BuildException(
+                    "Invalid coreLoader - it "
+                    + "returns an incorrect Project.class");
+            }
+        } catch (Exception ex) {
+            throw new BuildException("unable to use coreloader", ex);
+        }
+        ComponentHelper.getComponentHelper(this)
+            .resetCoreLoader(this.coreLoader, coreLoader);
         this.coreLoader = coreLoader;
     }
 
--- src/main/org/apache/tools/ant/taskdefs/Classloader.java	(revision 446566)
+++ src/main/org/apache/tools/ant/taskdefs/Classloader.java	(working copy)
@@ -167,7 +167,6 @@ 
             }
 
             AntClassLoader acl = (AntClassLoader) obj;
-
             if (acl == null) {
                 // Construct a new class loader
                 Object parent = null;
@@ -197,8 +196,13 @@ 
 
                 if (name == null) {
                     // This allows the core loader to load optional tasks
-                    // without delegating
-                    acl.addLoaderPackageRoot("org.apache.tools.ant.taskdefs.optional");
+                    // and types without delegating
+                    acl.addLoaderPackageRoot(
+                        "org.apache.tools.ant.taskdefs.optional");
+                    acl.addLoaderPackageRoot(
+                        "org.apache.tools.ant.types.optional");
+                    acl.addLoaderPackageRoot(
+                        "org.apache.tools.ant.util.optional");
                     getProject().setCoreLoader(acl);
                 }
             }
@@ -214,10 +218,9 @@ 
                 }
             }
 
-            // XXX add exceptions
-
         } catch (Exception ex) {
-            ex.printStackTrace();
+            throw new BuildException(ex);
         }
     }
 }
--- src/main/org/apache/tools/ant/AntTypeDefinition.java	(revision 446566)
+++ src/main/org/apache/tools/ant/AntTypeDefinition.java	(working copy)
@@ -56,7 +56,14 @@ 
     }
 
     /**
+     * Return the current value of clazz.
+     */
+    protected Class getClazz() {
+        return clazz;
+    }
+
+    /**
      * Set the class of the definition.
      * As a side-effect may set the classloader and classname.
      * @param clazz the class of this definition.