Nested class in Java With Example

→ class inside a class is called nested class.

→ The Main Purpose of Nested Class make the group classes that belong together which makes your code more readable and maintainable.

Syntax

 class OuterClass { 
           //code
class InnerClass{
        //code
    }
}
 

Example :-

 class OuterClass {
  int x = 5;
  class InnerClass {
    int y = 10;
  }}
 public class TestNest {
  public static void main(String[] args) {
    OuterClass o = new OuterClass();
    OuterClass.InnerClass i = o.new InnerClass();
    System.out.println(i.y + o.x);
  }}

Output :-

Advantage of nested class in java:

code Optimization
Easy to understand.
It can access all the member of outer class including private.
Nested classes can access all the members (data members and methods) of outer class including private.
As nested classes are logically grouped classes and interfaces in one place so that it is use to develop more readable and maintainable code.
Nested classes helps to write optimized code, as it require less code to write.

Types of Nested class in java.

Next TopicMember Inner Class in Java

← prev next →