Preserving stack trace in exception.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/proxy/branches/version-2.0-work@1510015 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/core/src/main/java/org/apache/commons/proxy2/provider/CloningProvider.java b/core/src/main/java/org/apache/commons/proxy2/provider/CloningProvider.java
index 32194d3..ab361dc 100644
--- a/core/src/main/java/org/apache/commons/proxy2/provider/CloningProvider.java
+++ b/core/src/main/java/org/apache/commons/proxy2/provider/CloningProvider.java
@@ -90,7 +90,7 @@
         catch (NoSuchMethodException e)

         {

             throw new ObjectProviderException(

-                    String.format("Class %s does not have a clone() method (should never happen).", cloneable.getClass().getName()));

+                    String.format("Class %s does not have a clone() method (should never happen).", cloneable.getClass().getName()), e);

         }

     }