Thanks for your comment, after that I've come to read about it in the Java Persistence Wikibook I've found the cause of the problem.
https://en.wikibooks.org/wiki/Java_Persistence/OneToMany#Getters_and_Setters Last two paragraphs: / Some expect the JPA provider to have magic that automatically maintains relationships. This was actually part of the EJB CMP 2 specification. However the issue is if the objects are detached or serialized to another VM, or new objects are related before being managed, or the object model is used outside the scope of JPA, then the magic is gone, and the application is left figuring things out, so in general it may be better to add the code to the object model. However some JPA providers do have support for automatically maintaining relationships. In some cases it is undesirable to instantiate a large collection when adding a child object. One solution is to not map the bi-directional relationship, and instead query for it as required. Also some JPA providers optimize their lazy collection objects to handle this case, so you can still add to the collection without instantiating it. / It seems to me that in the original application (EJB CMP2) the relationships were bi-directional, and because of that this "magic" of maintaining the two sides of the relationship was done automatically. So now that I use OpenEJB with JPA I have to do this "magic" manually and delete all bi-directional relationships which are likelly to get really big. Thanks for your comments. Tomás -- View this message in context: http://tomee-openejb.979440.n4.nabble.com/Problem-with-Tomee-on-ejbPostCreate-method-OutOfMemoryError-tp4676642p4676652.html Sent from the TomEE Users mailing list archive at Nabble.com.
