What happens when I merge an object in Hibernate?

Question

In my project, some time I have to load a object to edit them. Before this, I think, hibernate session is closed.

Some time before save the edited object (with saveOrUpdate ), I have to search (open session again) for a object in the database, and, maybe, the object returned by this search is the object I'll update. (I need this object for some validations and other things...)

After this, when I try to save the object, hibernate says that I have another object with the same identifier in the session.

I have implemented my own equals and hashcode methods, and I tried to do somethings, like session.evict(object) , but, nothing works.

So, I use session.merge(object) instead of session.saveOrUpdate(object) , and it works. But, I dont know exactly what is the consequences of doing this. I can simple replace saveOrUpdate by merge , or I will get some issues with it? Another thing I have to know about this?

Thanks in advance.

Answer 1

i think this is a duplicate for What are the differences between Hibernate Session methods saveOrUpdate() and merge()? and a number of other questions, very common question indeed...