Review Questions


graphics/rq_icon.gif
6.25

What will be the result of attempting to compile and run the following program?

 public class Polymorphism {     public static void main(String[] args) {         A ref1 = new C();         B ref2 = (B) ref1;         System.out.println(ref2.f());     } } class A           { int f() { return 0; } } class B extends A { int f() { return 1; } } class C extends B { int f() { return 2; } } 

Select the one correct answer.

  1. The program will fail to compile.

  2. The program will compile without error, but will throw a ClassCastException when run.

  3. The program will compile without error and print when run.

  4. The program will compile without error and print 1 when run.

  5. The program will compile without error and print 2 when run.

6.26

What will be the result of attempting to compile and run the following program?

 public class Polymorphism2 {     public static void main(String[] args) {         A ref1 = new C();         B ref2 = (B) ref1;         System.out.println(ref2.g());     } } class A {     private int f() { return 0; }     public int g() { return 3; } } class B extends A {     private int f() { return 1; }     public int g() { return f(); } } class C extends B {     public int f() { return 2; } } 

Select the one correct answer.

  1. The program will fail to compile.

  2. The program will compile without error and print when run.

  3. The program will compile without error and print 1 when run.

  4. The program will compile without error and print 2 when run.

  5. The program will compile without error and print 3 when run.



A Programmer[ap]s Guide to Java Certification
A Programmer[ap]s Guide to Java Certification
ISBN: 201596148
EAN: N/A
Year: 2003
Pages: 284

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net