Index: openjpa-kernel/src/main/java/org/apache/openjpa/enhance/PCRegistry.java
===================================================================
--- openjpa-kernel/src/main/java/org/apache/openjpa/enhance/PCRegistry.java	(revision 556794)
+++ openjpa-kernel/src/main/java/org/apache/openjpa/enhance/PCRegistry.java	(working copy)
@@ -20,6 +20,7 @@
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.Map;
@@ -27,6 +28,7 @@
 import org.apache.openjpa.lib.util.Localizer;
 import org.apache.openjpa.lib.util.ReferenceMap;
 import org.apache.openjpa.lib.util.concurrent.ConcurrentReferenceHashMap;
+import org.apache.openjpa.util.InternalException;
 import org.apache.openjpa.util.UserException;
 
 /**
@@ -44,6 +46,19 @@
     // map of pc classes to meta structs; weak so the VM can GC classes
     private static final Map _metas = new ConcurrentReferenceHashMap
         (ReferenceMap.WEAK, ReferenceMap.HARD);
+    
+    private static final Map _primitives = new HashMap();
+    static {
+    	_primitives.put("boolean", boolean.class);
+    	_primitives.put("byte",    byte.class);
+    	_primitives.put("char",    char.class);
+    	_primitives.put("double",  double.class);
+    	_primitives.put("float",   float.class);
+    	_primitives.put("int",     int.class);
+    	_primitives.put("long",    long.class);
+    	_primitives.put("short",   short.class);
+   }
+    
 
     // register class listeners
     private static final Collection _listeners = new LinkedList();
@@ -88,8 +103,35 @@
      */
     public static Class[] getFieldTypes(Class pcClass) {
         Meta meta = getMeta(pcClass);
-        return meta.fieldTypes;
+        String[] fieldTypes = meta.fieldTypes;
+        Class[] result = new Class[fieldTypes.length];
+        ClassLoader fieldLoader = pcClass.getClassLoader();
+        for (int i=0; i<fieldTypes.length; i++) {
+            result[i] = getClassForName(fieldTypes[i], fieldLoader, 
+                " type of " + pcClass.getName()+"."+getFieldNames(pcClass)[i]); 
+        }
+        return result;
     }
+    
+    static boolean isPrimitive(String t) {
+    	return _primitives.containsKey(t);
+    }
+    
+    static Class getPrimitive(String t) {
+    	return (Class)_primitives.get(t);
+    }
+    
+    static Class getClassForName(String name, ClassLoader loader, String ctx) {
+    	if (name == null)
+    		return null;
+    	try {
+    		return isPrimitive(name) ? getPrimitive(name) 
+    			: Class.forName(name, false, loader);
+    	} catch (Throwable t) {
+			throw new InternalException(_loc.get("registry-load-error",
+				new Object[]{ctx, name, loader, t}).toString());
+    	}
+    }
 
     /**
      * Return the persistent superclass for a <code>PersistenceCapable</code>
@@ -98,7 +140,8 @@
      */
     public static Class getPersistentSuperclass(Class pcClass) {
         Meta meta = getMeta(pcClass);
-        return meta.pcSuper;
+        return getClassForName(meta.pcSuper, pcClass.getClassLoader(), 
+        	"super class of " + pcClass.getName());
     }
 
     /**
@@ -110,7 +153,7 @@
         Meta meta = getMeta(pcClass);
         return (meta.pc == null) ? null : meta.pc.pcNewInstance(sm, clear);
     }
-
+    
     /**
      * Create a new instance of the class and assign its state manager and oid.
      * The new instance has its flags set to <code>LOAD_REQUIRED</code>.
@@ -238,22 +281,27 @@
 
     /**
      * This is a helper class to manage metadata per persistence-capable class.
+     * The type information is maintained as class names rather than Class
+     * to allow garbage collection.
      */
     private static class Meta {
 
         public final PersistenceCapable pc;
         public final String[] fieldNames;
-        public final Class[] fieldTypes;
-        public final Class pcSuper;
+        public final String[] fieldTypes;
+        public final String pcSuper;
         public final String alias;
 
         public Meta(PersistenceCapable pc, String[] fieldNames,
             Class[] fieldTypes, Class pcSuper, String alias) {
             this.pc = pc;
             this.fieldNames = fieldNames;
-            this.fieldTypes = fieldTypes;
-            this.pcSuper = pcSuper;
+            this.pcSuper = (pcSuper == null) ? null : pcSuper.getName();
 			this.alias = alias;
+			this.fieldTypes = new String[fieldTypes.length];
+			for (int i=0; i<fieldTypes.length; i++) {
+				this.fieldTypes[i] = fieldTypes[i].getName();
+			}
 		}
 	}
 }
Index: openjpa-kernel/src/main/resources/org/apache/openjpa/enhance/localizer.properties
===================================================================
--- openjpa-kernel/src/main/resources/org/apache/openjpa/enhance/localizer.properties	(revision 556794)
+++ openjpa-kernel/src/main/resources/org/apache/openjpa/enhance/localizer.properties	(working copy)
@@ -121,3 +121,5 @@
 	field "{1}", while the getter method returns field "{2}".
 cft-exception-thrown: An exception was thrown while attempting to perform \
 	class file transformation on "{0}":
+registry-load-error: Following exception was thrown while "{2}" tried to  \
+	load the class "{1}" as "{0}": {3}