fixed exception propagation issue with Hessian 4.0 (SPR-6899)

org.springframework.web/src/main/java/org/springframework/remoting/caucho/HessianClientInterceptor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2010 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -223,6 +223,10 @@ public class HessianClientInterceptor extends UrlBasedRemoteAccessor implements
 		}
 		catch (InvocationTargetException ex) {
 			Throwable targetEx = ex.getTargetException();
+			// Hessian 4.0 check: another layer of InvocationTargetException. 
+			if (targetEx instanceof InvocationTargetException) {
+				targetEx = ((InvocationTargetException) targetEx).getTargetException();
+			}
 			if (targetEx instanceof HessianConnectionException) {
 				throw convertHessianAccessException(targetEx);
 			}