abstract class demonstration

// A Simple demonstration of abstract. 
abstract class A { 
abstract void callme(); 
// concrete methods are still allowed in abstract classes 
void callmetoo() { 
System.out.println("This is a concrete method."); 
} 
}

class B extends A { 
void callme() { 
System.out.println("B's implementation of callme."); 
} 
}

class AbstractDemo { 
public static void main(String args[]) { 
B b = new B(); 
b.callme(); 
b.callmetoo(); 
} 
}