Index: xml/src/main/java/org/exolab/castor/xml/util/JDOClassDescriptorResolverImpl.java
===================================================================
--- xml/src/main/java/org/exolab/castor/xml/util/JDOClassDescriptorResolverImpl.java	(revision 7639)
+++ xml/src/main/java/org/exolab/castor/xml/util/JDOClassDescriptorResolverImpl.java	(working copy)
@@ -1,26 +1,63 @@
 package org.exolab.castor.xml.util;
 
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
 
 import org.exolab.castor.mapping.ClassDescriptor;
 import org.exolab.castor.mapping.MappingLoader;
 import org.exolab.castor.xml.ClassDescriptorResolver;
 import org.exolab.castor.xml.ResolverException;
+import org.exolab.castor.xml.util.resolvers.ResolveHelpers;
 
 public class JDOClassDescriptorResolverImpl implements ClassDescriptorResolver {
 
-    private Map _classToClassDescriptors = new HashMap();
+    /**
+     * File name prefix used for JDO-specific descriptor classes.
+     */
+    private static final String JDO_DESCRIPTOR_PREFIX = "JDO";
+
+    /**
+     * File name suffix used for JDO-specific descriptor classes.
+     */
+    private static final String JDO_DESCRIPTOR_SUFFIX = "Descriptor";
+
+    /**
+     * Package name of the sub-package where descriptors can be found.
+     */
+    private static final String JDO_DESCRIPTOR_PACKAGE = "descriptors";
+    
+    /**
+     * A key ({@link Class}) value ({@link ClassDescriptor}) 
+     * pair to cache already resolved jdo class descriptors. 
+     */
+    private Map _classDescriptorCache = new HashMap();
+
     private MappingLoader _mappingLoader;
 
+    /**
+     * List of manually added domain <code>Class</code>es.
+     */
+    private List _classes = new LinkedList();
+
     public JDOClassDescriptorResolverImpl() {
         super();
     }
 
     /**
-     * Returns the ClassDescriptor for the given class
-     *
-     * @param type the Class to find the ClassDescriptor for
+     * Returns the ClassDescriptor for the given class using the following
+     * strategy.<br><br>
+     * <ul>
+     * <li>Lookup the class descriptor cache
+     * <li>Call {@link JDOClassDescriptorResolverImpl#loadClassDescriptor(Class)}
+     * <li>Ask the {@link MappingLoader}
+     * </ul>
+     * 
+     * @param type
+     *            the Class to find the ClassDescriptor for
      * @return the ClassDescriptor for the given class
      */
     public ClassDescriptor resolve(Class type) throws ResolverException {
@@ -28,43 +65,97 @@
             return null;
         }
 
+        ClassDescriptor classDesc;
+
         // TODO: use ClassDescriptor instead
-        ClassDescriptor classDesc = (ClassDescriptor) _classToClassDescriptors.get(type);
+        classDesc = (ClassDescriptor) _classDescriptorCache.get(type);
+        if (classDesc != null) {
+            return classDesc;
+        }
 
+        classDesc = loadClassDescriptor(type);
         if (classDesc != null) {
             return classDesc;
         }
 
-        // -- check mapping loader first
+        // -- check mapping
         if (_mappingLoader != null) {
             classDesc = _mappingLoader.getDescriptor(type.getName());
             if (classDesc != null) {
-                _classToClassDescriptors.put(type, classDesc);
+                _classDescriptorCache.put(type, classDesc);
                 return classDesc;
             }
         }
 
         // TODO: consider for future extensions
 
-// String pkgName = getPackageName(type.getName());
-//
-// //-- check package mapping
-// Mapping mapping = loadPackageMapping(pkgName, type.getClassLoader());
-// if (mapping != null) {
-// try {
-// MappingLoader mappingLoader = mapping.getResolver(BindingType.JDO);
-// classDesc = mappingLoader.getDescriptor(type);
-// }
-// catch(MappingException mx) {}
-// if (classDesc != null) {
-// associate(type, classDesc);
-// return classDesc;
-// }
-// }
+        // String pkgName = getPackageName(type.getName());
+        //
+        // //-- check package mapping
+        // Mapping mapping = loadPackageMapping(pkgName, type.getClassLoader());
+        // if (mapping != null) {
+        // try {
+        // MappingLoader mappingLoader = mapping.getResolver(BindingType.JDO);
+        // classDesc = mappingLoader.getDescriptor(type);
+        // }
+        // catch(MappingException mx) {}
+        // if (classDesc != null) {
+        // associate(type, classDesc);
+        // return classDesc;
+        // }
+        // }
 
         return classDesc;
     } // -- resolve
 
+    /**
+     * Tries to load a {@link ClassDescriptor} for the given type 
+     * from the filesystem using a {@link ClassLoader} by
+     * <ul>
+     * <li>Lookup the same package</li>
+     * <li>Lookup the subpackage <code>descriptors</code></li>
+     * </ul>.
+     * 
+     * @param type to lookup the descriptor for.
+     * @return an instance of ClassDescriptor if found. null if not.
+     */
+    private ClassDescriptor loadClassDescriptor(final Class type) {
+        ClassDescriptor classDesc = null;
+        ClassLoader classLoader = type.getClassLoader();
+        StringBuffer descriptorClassName = new StringBuffer(type.getName());
+        descriptorClassName.append(JDO_DESCRIPTOR_PREFIX);
+        descriptorClassName.append(JDO_DESCRIPTOR_SUFFIX);
+        // Try to load descriptor in the same package
+        Class descriptorClass = ResolveHelpers.loadClass(
+                classLoader, descriptorClassName.toString());
+
+        // If descriptor was not found, lookup the descriptor package
+        if (descriptorClass == null) {
+            int offset = descriptorClassName.lastIndexOf(".");
+            if (offset != -1) {
+                descriptorClassName.insert(offset , ".");
+                descriptorClassName.insert(offset + 1, JDO_DESCRIPTOR_PACKAGE);
+                descriptorClass = ResolveHelpers.loadClass(
+                        classLoader, descriptorClassName.toString());
+            }
+        }
+        
+        // Descriptor was found, instantiate and return it
+        if (descriptorClass != null) {
+            try {
+                classDesc = (ClassDescriptor) descriptorClass.newInstance();
+                // Put descriptor into cache
+                _classDescriptorCache.put(type.getName(), classDesc);
+                return classDesc;
+            } catch (InstantiationException e) {
+                new RuntimeException(e.getMessage());
+            } catch (IllegalAccessException e) {
+                new RuntimeException(e.getMessage());
+            }
+        }
+        return classDesc;
+    }
+
     public MappingLoader getMappingLoader() {
         return _mappingLoader;
     }
@@ -73,4 +164,24 @@
         this._mappingLoader = mappingLoader;
     }
 
+    public void addClass(Class domainClass) {
+        _classes.add(domainClass);
+    }
+
+    /**
+     * Returns an iterator over all the known descriptors in the original order they have been
+     * added. Each element is of type {@link ClassDescriptor}.
+     */
+    public Iterator descriptorIterator() {
+        List allDescriptors = new ArrayList();
+        allDescriptors.addAll(_mappingLoader.getDescriptors());
+        for (Iterator iterator = _classes.iterator(); iterator.hasNext();) {
+            allDescriptors.add(loadClassDescriptor((Class) iterator.next()));
+        }
+        return allDescriptors.iterator();
+    }
+    
+    public ClassLoader getClassLoader() {
+        return _mappingLoader.getClassLoader();
+    }
 }
Index: xml/src/main/java/org/exolab/castor/mapping/MappingLoader.java
===================================================================
--- xml/src/main/java/org/exolab/castor/mapping/MappingLoader.java	(revision 7639)
+++ xml/src/main/java/org/exolab/castor/mapping/MappingLoader.java	(working copy)
@@ -45,6 +45,7 @@
 package org.exolab.castor.mapping;
 
 import java.util.Iterator;
+import java.util.List;
 
 import org.castor.mapping.BindingType;
 
@@ -89,4 +90,10 @@
      * added. Each element is of type {@link ClassDescriptor}.
      */
     Iterator descriptorIterator();
+    
+    /**
+     * Returns a List of {@link ClassDescriptor}s of all known descriptors.
+     * @return List of {@link ClassDescriptor}
+     */
+    List getDescriptors();
 }
Index: xml/src/main/java/org/exolab/castor/mapping/loader/AbstractMappingLoader2.java
===================================================================
--- xml/src/main/java/org/exolab/castor/mapping/loader/AbstractMappingLoader2.java	(revision 7639)
+++ xml/src/main/java/org/exolab/castor/mapping/loader/AbstractMappingLoader2.java	(working copy)
@@ -129,6 +129,10 @@
         return _descriptors.iterator();
     }
 
+    public final List getDescriptors() {
+        return _descriptors;
+    }
+    
     //--------------------------------------------------------------------------
     
     /**