POJO class in Java

POJO  :  Plain Old Java Object

1. POJO class is a simple Java class.

2. The classes that does not implement any technology/framework  API interfaces and that does not extend  any technology framework  API classes.

3. It can extends and implement from Java (JEE) language.

Examples

Example 1

class Demo { 
  
// implementation goes here

}

Given class is POJO because it is simple java language class

Example 2

class Demo extends HttpServlet {

// implementation goes here

}

Given class is Not POJO because it extend Servlet technology class

Example 3

class Demo implents Serializable {

// implementation goes here

}


Given class is POJO because it implement java language serializable

Example 4

@Entity
class Demo {

// implementation goes here

}

// Given class is POJO, 
//if a class uses only annotation then it is POJO 

Example 5

class Demo extends Test {

// implementation goes here

}
// if Test is POJO, Demo also POJO