What is the difference between POJO and Java Bean ?

POJO refers to Plain Old Java Object

Both POJO and Bean are used to access private variable via public getters and setters

A JavaBean is a POJO that is serializable, has a no-argument constructor, and allows access to properties using getter and setter methods.

As designs using POJOs have become more commonly-used, systems have arisen that give POJOs some of the functionality used in frameworks and more choice about which areas of functionality are actually needed. Hibernate and Spring are examples.