What is the difference between a JavaBean and a PO

Question

I'm not sure about the difference. I'm using Hibernate and, in some books, they use JavaBean and POJO as an interchangeable term. I want to know if there is a difference, not just in the Hibernate context, but as general concepts.

Answer 1

You've seen the formal definitions above, for all they are worth.

But don't get too hung up on definitions. Let's just look more at the sense of things here.

JavaBeans are used in Enterprise Java applications, where users frequently access data and/or application code remotely, i.e. from a server (via web or private network) via a network. The data involved must therefore be streamed in serial format into or out of the users' computers - hence the need for Java EE objects to implement the interface Serializable. This much of a JavaBean's nature is no different to Java SE application objects whose data is read in from, or written out to, a file system. Using Java classes reliably over a network from a range of user machine/OS combinations also demands the adoption of conventions for their handling. Hence the requirement for implementing these classes as public, with private attributes, a no-argument constructor and standardised getters and setters.

Java EE applications will also use classes other than those that were implemented as JavaBeans. These could be used in processing input data or organizing output data but will not be used for objects transferred over a network. Hence the above considerations need not be applied to them bar that the be valid as Java objects. These latter classes are referred to as POJOs - Plain Old Java Objects.

All in all, you could see Java Beans as just Java objects adapted for use over a network.

There's an awful lot of hype - and no small amount of humbug - in the software world since 1995.