Why cascade merge didn’t work

Problem

I ran into a problem with JPA not saving my related entities when I merged them, even though I had set cascade to persist.

Solution

It turns out that both Cascade.PERSIST and Cascade.MERGE have to be specified on a JPA entity. Just PERSIST does not apply to situations were an existing entity is merged after having been linked to new entities.

How to use Bean Managed Transactions with EJB3, JPA and JTA

During a “little” project I am doing in my spare time, I found out that switching to Bean Managed Transactions (BMT) wasn’t as easy as I expected. When you’ve used Container Managed Transactions (CMT) and are switching to BMT with JTA like I was, you need to know the following: