All Veterans,

I am kind of new and don't completely understand how Serializable POJO is benefitable from Hibernate if there is any.

If each id field is already Serializable data type such as Long, then making entire POJO Serializable really necessary?

Would anyone can explain how this(Serializable or not) make different in real simple words?

I am trying to figure out which POJOs has to be Serializable.

Java Baby.

Hibernate does not require that the object be serializable. In practice; however, most people do make their POJO's serializable for the following reasons:

It allows the object to be passed to an EJB.
It allows the object to be stored in a servlet session.
It may be required for some implementations of clustering and/or caching.

In general, it does not hurt and it usually helps.