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  • Question
  • What will be the output of the program?
    class Tree { } 
    class Pine extends Tree { } 
    class Oak extends Tree { } 
    public class Forest1 
    { 
        public static void main (String [] args)
        { 
            Tree tree = new Pine(); 
            if( tree instanceof Pine ) 
                System.out.println ("Pine"); 
            else if( tree instanceof Tree ) 
                System.out.println ("Tree"); 
            else if( tree instanceof Oak ) 
                System.out.println ( "Oak" ); 
            else 
                System.out.println ("Oops "); 
        } 
    }
    


  • Options
  • A. Pine
  • B. Tree
  • C. Forest
  • D. Oops

  • Correct Answer
  • Pine 

    Explanation
    The program prints "Pine".

    More questions

    • 1. Which of the following class level (nonlocal) variable declarations will not compile?

    • Options
    • A. protected int a;
    • B. transient int b = 3;
    • C. private synchronized int e;
    • D. volatile int d;
    • Discuss
    • 2. Which interface provides the capability to store objects using a key-value pair?

    • Options
    • A. Java.util.Map
    • B. Java.util.Set
    • C. Java.util.List
    • D. Java.util.Collection
    • Discuss
    • 3. What is the numerical range of char?

    • Options
    • A. 0 to 32767
    • B. 0 to 65535
    • C. -256 to 255
    • D. -32768 to 32767
    • Discuss
    • 4. Assume the following method is properly synchronized and called from a thread A on an object B:

      wait(2000);

      After calling this method, when will the thread A become a candidate to get another turn at the CPU?


    • Options
    • A. After thread A is notified, or after two seconds.
    • B. After the lock on B is released, or after two seconds.
    • C. Two seconds after thread A is notified.
    • D. Two seconds after lock B is released.
    • Discuss
    • 5. Which three are valid declarations of a char?

      1. char c1 = 064770;
      2. char c2 = 'face';
      3. char c3 = 0xbeef;
      4. char c4 = \u0022;
      5. char c5 = '\iface';
      6. char c6 = '\uface';

    • Options
    • A. 1, 2, 4
    • B. 1, 3, 6
    • C. 3, 5
    • D. 5 only
    • Discuss
    • 6. What will be the output of the program?
      class A 
      {
          final public int GetResult(int a, int b) { return 0; } 
      } 
      class B extends A 
      { 
          public int GetResult(int a, int b) {return 1; } 
      } 
      public class Test 
      {
          public static void main(String args[]) 
          { 
              B b = new B(); 
              System.out.println("x = " + b.GetResult(0, 1));  
          } 
      }
      

    • Options
    • A. x = 0
    • B. x = 1
    • C. Compilation fails.
    • D. An exception is thrown at runtime.
    • Discuss
    • 7. What will be the output of the program?
      public class Switch2 
      {
          final static short x = 2;
          public static int y = 0;
          public static void main(String [] args) 
          {
              for (int z=0; z < 4; z++) 
              {
                  switch (z) 
                  {
                      case x: System.out.print("0 ");
                      default: System.out.print("def ");
                      case x-1: System.out.print("1 ");  
                                  break;
                      case x-2: System.out.print("2 ");
                  }
              }
          }
      }
      

    • Options
    • A. 0 def 1
    • B. 2 1 0 def 1
    • C. 2 1 0 def def
    • D. 2 1 0 def 1 def 1
    • Discuss
    • 8. What will be the output of the program?
      import java.util.*; 
      class H 
      {
          public static void main (String[] args) 
          { 
              Object x = new Vector().elements(); 
              System.out.print((x instanceof Enumeration)+","); 
              System.out.print((x instanceof Iterator)+","); 
              System.out.print(x instanceof ListIterator); 
          } 
      }
      

    • Options
    • A. Prints: false,false,false
    • B. Prints: false,false,true
    • C. Prints: false,true,false
    • D. Prints: true,false,false
    • Discuss
    • 9. Which statement is true?

    • Options
    • A. A try statement must have at least one corresponding catch block.
    • B. Multiple catch statements can catch the same class of exception more than once.
    • C. An Error that might be thrown in a method must be declared as thrown by that method, or be handled within that method.
    • D. Except in case of VM shutdown, if a try block starts to execute, a corresponding finally block will always start to execute.
    • Discuss
    • 10. Which statement is true about assertions in the Java programming language?

    • Options
    • A. Assertion expressions should not contain side effects.
    • B. Assertion expression values can be any primitive type.
    • C. Assertions should be used for enforcing preconditions on public methods.
    • D. An AssertionError thrown as a result of a failed assertion should always be handled by the enclosing method.
    • Discuss


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