abstract class Animal{//abstract parent class //abstract method public abstract void sound(); } //Dog class extends Animal class public class Dog extends Animal{ public void sound(){ System.out.println("Wolf"); } public static void main(String args[]){ Animal obj = new Dog(); obj.sound(); } }

example:

Wolf

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Declaration : Abstract class

//Declaration using abstract keyword
abstract class A{
   //This is abstract method
   abstract void myMethod();
   //This is concrete method with body
   void anotherMethod(){
      //Does something
   }