src/share/classes/com/sun/jmx/mbeanserver/MXBeanMapping.java

@@ -167,11 +167,11 @@
     private static Class<?> makeOpenClass(Type javaType, OpenType<?> openType) {
         if (javaType instanceof Class<?> && ((Class<?>) javaType).isPrimitive())
             return (Class<?>) javaType;
         try {
             String className = openType.getClassName();
-            return Class.forName(className, false, null);
+            return Class.forName(className, false, MXBeanMapping.class.getClassLoader());
         } catch (ClassNotFoundException e) {
             throw new RuntimeException(e);  // should not happen
         }
     }