I have attached an updated version of the test case which now adds a test for jpa on Weblogic with a JTA transaction manager without the use of Spring: test.hhh9888_4.zip. This was quite a challenge but managed to do it.

The stack trace now only shows hibernate and weblogic classes: hopefully this will bring clarity on where things go wrong. See jpa_stack_trace.txt .

In this execution: i.e. a database constraint violation occurring within JPA using Hibernate, the original cause of the error is lost. This is exactly what this issue is about. The test case is relevant.