Java Programming Questions (Multiple Choice)

** Please only answer if you know it, not just copy and paste from another user. Please explain the answer.

1) Given code:

public abstract class A{ }

public class B extends A

{

}

The following code sequence would correctly create an object reference of class A holding an object reference for an object of class B:

A c;

c = new B();

	TRUE
	FALSE

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

2) After the following code sequence is executed, what are the contents at ArrayList index 1 in a?

ArrayList a = new ArrayList();

a.add(7);

a.add(10);

a.add(21);

a.set(1,4);

a.remove(0);

a	10
b	7
c	4
d	21

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

3) For this question, consider the following two classes:

public abstract class C

{

public void foo1()

{

System.out.println("Hello foo1");

}

public abstract void foo2();

public abstract void foo3();

public void foo1Call()

{

foo1();

}

}

public class D extends C

{

public void foo2()

{

System.out.println("Hello foo2");

}

public void foo4()

{

System.out.println("Hello D foo4()");

}

}

Which of the following code sequences, if any, will successfully access private method foo1 in class C?

a	C c2 = new C(); c2.foo1();
b	C c2 ; c2 = new D(); c2.foo1();
c	D d1 = new D(); d1.foo1();
d	C c1 = new D(); c1.foo1Call();
e	None of the above