Abstract Class In Java With Example | Full Stack With Java Course by Pankaj Sir
Abstract Class in Java :
- An Abstract Class Can Consist of Both Complete and incomplete Methods.
- An Abstract Class Can Consist of Static and non-Static Members.
- An Abstract Class is Zero to 100% incomplete.
- An Abstract Class Can Consist of Main Method.
- Object of abstract Class can not be Created but Reference Variable of abstract Class Can be Created.
Example 1
public abstract class A {
public void test1() { // correct
}
public void test2(); // Error
public abstract void test3(); // correct
}
Example 2
public abstract class A {
abstract public void test();
}
public class B extends A {
@Override
public void test(){
System.out.println(20);
}
public static void main ( String[] args ){
B b1 = new B();
b1.test();
}
}
Output : 20
Very Important Point of An Abstract Class
- Abstract Class does Not Support Multiple Inheritance.
Example 3
public abstract class A {
}
public abstract class B {
}
public abstract class C extends A,B { // Error
}
2. interface to Class and interface to abstract class Allowed but class to interface and abstract class to interface not Allowed

Example 4
public interface A {
public void test();
}
public abstract class B implements A {
}
public class C extends B {
@Override
public void test() {
System.out.println(100);
}
public static void main( String[] args ) {
C c1 = new C();
c1.test();
}
}
Output : 100
Difference Between Abstract Class and Interface
Sr No. | Abstract Class | Interface |
1 | Cannot Support Multiple Inheritance | Supports Multiple Inheritance |
2 | Can Create Static / Non- Static Variables | All Variables By Default are Static and Final |
3 | An Abstract Class can be 0 to 100% incomplete | Interfaces are 100% incomplete. |