Question

write exactly what the following code prints. Ensure that you write in the correct order. clearly distinguish scratch work from your final answer.

Public class Base{

public void m1(Base a){

System.out.println("Base m1");

a.m2();

}

public void m2(){

System.out.println("Base m2");

}

}

Public class Derived1 extends Base{

public void m1(Base b){

System.out.println("Derived1 m1");

}

public void m2(){

System.out.println("Derived1 m2");

}

}

Public class Derived2 extends Base{

public void m2(){

System.out.m2(){

System.out.println("Dertived2 m2");

}

}

public class UserBaseAndDerived1And2{

public static void main(String[] args){

Base b = new Base();

Derived1 d1 = new Derived1();

Derived2 d2 = new Derived2();

b.m1(b);

b.m1(d1);

b.m1(d2);

b =d1;

b.m1(d2);

b = d2;

b.m1(d1);

}

}

Answer 1

Output:

Base m1
Base m2
Base m1
Derived1 m2
Base m1
Dertived2 m2
Derived1 m1
Base m1
Derived1 m2

// here calling m1() with object type Base so it will execute base class m1()
       // from there we are calling m2 which executes in m2()
       b.m1(b);
       // here calling m1() with object type Base so it will execute base class m1()
       // passing d1 object if type Dereived1 so m2() will called using d1 so it will execute m2() in the Derived1 class
       b.m1(d1);
       // here calling m1() with object type Base so it will execute base class m1()
       // passing d2 object if type Dereived2 so m2() will called using d1 so it will execute m2() in the Derived2 class
       b.m1(d2);
       //now b is pointing to Derived1 class object
       b = d1;
//calling m1() using b, now b is pointing Derived1 object so it will execute m1() in Derived1
// calling m2() using d2 so it will call in Derived2 class
       b.m1(d2);
// now b is pointing d2
       b = d2;
// now m1() in Derived2 will be executed
// passing d1 so m2() will be executed in Derived1
       b.m1(d1);