Why is a ConcurrentModificationException thrown and how to debug it

Question

I am using a Collection (a HashMap used indirectly by the JPA, it so happens), but apparently randomly the code throws a ConcurrentModificati

Answer 1

It sounds less like a Java synchronization issue and more like a database locking problem.

I don't know if adding a version to all your persistent classes will sort it out, but that's one way that Hibernate can provide exclusive access to rows in a table.

Could be that isolation level needs to be higher. If you allow "dirty reads", maybe you need to bump up to serializable.