Deployment Error in JPA When deploying empty synchronous process

When an empty, synchronous process is deployed, the deployment engine crashes with a duplicate key exception in the JPA hibernate API.

The process is structured as follows:

• receive, receiving an empty message as part=payload
• reply, replying with a non-initialized output var
• both placed in a sequence container named main
  I have attached to complete WSDL/BPEL Files to this bug to be able to reproduce it easily.

For testing, I have decided to add a BPEL:empty Empty Activity between the receive and the reply activity, and - guess what - it worked!

This bug is really annoying because I'd like to test the execution speed of an empty process and compare it to the performance of other processes. Measuring an empty process would have been a good possibility to measure the time that is required to load a process from the persistance api, instanciating it and doing the necessary Axis2 work.