Final keyword in java

Final keyword is used to restrict the user. You cannot change it after you made it final. Java final keyword is used to stop changing the value, stop method overriding & to stop inheritance. Final can be

•      variables

•      methods

•       classes

final variables

If you make any variable as final you cannot change the final value of it it will be a constant.

Ex:

public class Demo {

      

       public int MAX_VAL= 11;

      

       public void myMethod(){

               MAX_VAL= 12;

             

       }

       public static void main(String[] args) {

              Demo demo= new Demo();

              demo.myMethod();

       }

}

This will give u an compile error as we have changed the value of the MAX_VAL.

Final methods

Once the method is final you cannot override it.

Ex:

final classes

If u make the class final you cannot extend it.

Ex:

Coding example

public class TestRun {

       public static void main(String[] args) {

              Test test = new Test();

              System.out.println(test.p1);

       }

}

class Test{

       public double  p1=3.14;

       Test(){

              p1=2.14;

       }

}

How to avoid someone changing the p1 ?

We can have p1 as final. But when you make it as final you will get an error like this.