Why need detached entities in JPA?

Question

There are always so many questions related to issues with detached entities!

First, they often cause LazyInitializationException in Hibernate. Yes, there ar

Answer 1

For instance, suppose you have a RESTful interface with a method for retrieving an JSON-serialized object by its id to the caller and a method that receives an updated version of this object from the caller. An entity that passed through such serialization/deserialization will appear in a detached state.

check this, and read 3.3 merge