OCPJP Simulation Test 2

2

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Question: What is the answer of the following code?

  1 public abstract class Email {
  2   public String recipient;
  3   abstract final void sendEmail();
  4   public static void main(String args[]) {
  5     Email email = new XyzEmail();
  6     email.recipient = "John@xyznetwork.com";
  7     email.sendEmail();
  8   }
  9   static class XyzEmail extends Email {
 10     public final void sendEmail()  {
 11       System.out.println("Email is sent to " + recipient);
 12     }}}

Choice:
A. Email is sent to John@xyznetwork.com
B. Email is sent to null
C. A compiler error occurs on line 3
D. A compiler error occurs on line 7
E. A compiler error occurs on line 9
F. A RuntimeExeption is thrown
G. The program compiles but never finish executing
H. None of the above



Next Question

Answer: C

Explain: Explain: A static nested class can extend other classes, E is incorrect. You can not declare a method as both static and final. If final is removed, the answer is A. The compiler error is:

OCPJP>javac Email.java 

Email.java:3: error: illegal combination of modifiers: abstract and final

  abstract final void sendEmail();

                      ^

Email.java:10: error: sendEmail() in XyzEmail cannot override sendEmail() in Email

    public final void sendEmail()  {

                      ^

  overridden method is final

2 errors

Study:       Develop code that uses abstract classes and methods

     Develop code that uses final keyword

     Create inner classes including static inner class, local class, nested class, and anonymous inner class