Hey people, this is André AS from Brazil this is my first post here our forum...

Could you help me please understand what detached object is?

hi, it's important you understand the different states of you entities, like attached and detached. Please read the documentation: http://docs.jboss.org/hibernate/core/3.6/

In your case, you likely needed to use the "save(entity)" method, instead of "persist(entity)" as the entity is new.