POJO (Plain Old Java Object): The simpler...the better.

A POJO is simply an object built using a Java class that does not implement any special interfaces such as those defined by the EJB 2 framework. An example of a POJO is a class composed by only: Properties, representing the object’s state. Getter and setter methods for the properties. Business methods, representing behaviour. Some properties can represent associations with other POJOs. Here is an example of implementation of the Person entity using a POJO: