Answer Posted / ankur pandya

When we want to design such a method which is different for
every of its child class, means all the subclass has that
method with different behavior, then we declare the method
as ABSTRACT METHOD.
for eg.

------------------------------------------------------------

// file name "AbstractMethodDemo.java"

abstract class MyAbstractClass {
abstract void myAbstractClassMethod1(); // defination
done in DerivedClass class
void myAbstractClassMethod2(){
System.out.println("myAbstractClassMethod2()
method called from Parent Class..");
}
}

class DerivedClass1 extends MyAbstractClass {
void myAbstractClassMethod1(){
System.out.println(" myAbstractClassMethod1()
method Called form Derived Class-1..");
}
}

class DerivedClass2 extends MyAbstractClass {
void myAbstractClassMethod1(){
System.out.println(" myAbstractClassMethod1()
method Called form Derived Class-2..");
}
}

public class AbstractMethodDemo {
public static void main(String[] args) {

DerivedClass1 obj1 = new DerivedClass1();
obj1.myAbstractClassMethod1();
obj1.myAbstractClassMethod2();

DerivedClass2 obj2 = new DerivedClass2();
obj2.myAbstractClassMethod1();
obj2.myAbstractClassMethod2();

}
}

---------------------------------------------------------

Here myAbstractClassMethod1() is abstract because I want to
change its behaviour as Base classes, But
myAbstractClassMethod2() is not declared Abstract because I
want to keep its behaviour same for every base class.

Ans obvious, Abstract Method must be declared in Abstract Class.

I hope the defination is clear now..

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