You haven't mapped your primary key correctly,
you are probably using an auto-increment
in the db. You need to tell jboss this.
Use search in the CMP forum.
Thanks for setting me on the right track... you were exactly right, I was using MySQL's auto-increment on the primary key field and that was confusing JBoss. Here is the solution. I modified jbosscmp-jdbc.xml for the entity bean in question as follows:
<!-- added the following to handle auto-incement pk -->
<!-- end of handling auto-increment pk -->
There is a more complete discusson of this at: