OCPJP Simulation Test 5

5

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Question List

Question: What is the output of the following program?

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

Choice:
A. Message is sent to John@xyznetwork.com
B. Message is sent to null
C. Compile error at line 1
D. Compile error at line 7
E. Compile error at line 9
F. Compile error at line 10
G. Compile error at line 11



Next Question

Answer: A

Explain: abstract class can have 0 or more concrete methods or abstract methods, abstract class can also have static nested classes which extends it and overrides any concrete or abstract methods. The static nested class can access the variables none private variables defined in the enclosing class.

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