What is java pojo class, java bean, normal class?

Question

Possible Duplicate:
Difference between DTO, VO, POJO, JavaBeans?

Hi please don't say my question is duplicate :-) I saw all questions but didn't understand the exact difference.

Can someone explain what is POJO, Bean, Normal Class in easy language?

Answer 1

POJO stands for Plain Old Java Object, and would be used to describe the same things as a "Normal Class" whereas a JavaBean follows a set of rules. Most commonly Beans use getters and setters to protect their member variables, which are typically set to private and have a no-argument public constructor. Wikipedia has a pretty good rundown of JavaBeans: http://en.wikipedia.org/wiki/JavaBeans

POJO is usually used to describe a class that doesn't need to be a subclass of anything, or implement specific interfaces, or follow a specific pattern.

Answer 2

1. Normal Class: A Java class

2. Java Beans:

   • All properties private (use getters/setters)
   • A public no-argument constructor
   • Implements Serializable.

3. Pojo: Plain Old Java Object is a Java object not bound by any restriction other than those forced by the Java Language Specification. I.e., a POJO should not have to

   • Extend prespecified classes
   • Implement prespecified interface
   • Contain prespecified annotations

Answer 3

POJO = Plain Old Java Object. It has properties, getters and setters for respective properties. It may also override Object.toString() and Object.equals().

Java Beans : See Wiki link.

Normal Class : Any java Class.