How to solve "NullPointerException" with "Server.processing" error while we are using Flex Builder 3 and BlazeDS?

Question

I am using Flex builder 3, BlazeDS, and Java with Spring and Hibernate framework. I using the remote object to load a string from spring's configuration files. But in testing, I found this fault event like this:

RPC Fault faultString="java.lang.NullPointerException" faultCode="Server.Processing" faultDetail="null"

I have checked the configuration in remote-config.xml and services-config.xml. But it looks good. Some people have talked about this problem around the Internet and I think you can help me and them.

I am using these environment:

• Flex Builder 3
• BlazeDS 3.2.0
• JBoss server

Full stacktrace:

[RPC Fault faultString="java.lang.NullPointerException" faultCode="Server.Processing" faultDetail="null"]
 at mx.rpc::AbstractInvoker/http://www.adobe.com/2006/flex/mx/internal::faultHandler()[C:\autobuild\3.2.0\frameworks\projects\rpc\src\mx\rpc\AbstractInvoker.as:220]
 at mx.rpc::Responder/fault()[C:\autobuild\3.2.0\frameworks\projects\rpc\src\mx\rpc\Responder.as:53]
 at mx.rpc::AsyncRequest/fault()[C:\autobuild\3.2.0\frameworks\projects\rpc\src\mx\rpc\AsyncRequest.as:103]
 at NetConnectionMessageResponder/statusHandler()[C:\autobuild\3.2.0\frameworks\projects\rpc\src\mx\messaging\channels\NetConnectionChannel.as:569]
 at mx.messaging::MessageResponder/status()[C:\autobuild\3.2.0\frameworks\projects\rpc\src\mx\messaging\MessageResponder.as:222]

Answer 1

The java.lang.NullPointerException indicates an error being thrown on the server. To debug this, active debug logging on BlazeDS in the services-config.xml file. You should see detailed debug information in the server console.

Answer 2

When using the BlazeDS/Spring integration take care that you will need to use a custom exception translator in order to obtain meaningful exceptions. Please read this document http://static.springsource.org/spring-flex/docs/1.0.x/reference/html/ch02s08.html

In your case the error is not related to some configuration problems, it seems that is thrown inside your java method. Use a debugger in order to diagnose properly.