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  • Question
  • What will be the output of the program?
    try 
    {
        Float f1 = new Float("3.0");
        int x = f1.intValue();
        byte b = f1.byteValue();
        double d = f1.doubleValue();
        System.out.println(x + b + d);
    }
    catch (NumberFormatException e) /* Line 9 */
    {
        System.out.println("bad number"); /* Line 11 */
    }
    


  • Options
  • A. 9.0
  • B. bad number
  • C. Compilation fails on line 9.
  • D. Compilation fails on line 11.

  • Correct Answer
  • 9.0 

    Explanation
    The xxxValue() methods convert any numeric wrapper object's value to any primitive type. When narrowing is necessary, significant bits are dropped and the results are difficult to calculate.

    More questions

    • 1. What will be the output of the program?
      public class A
      { 
          void A() /* Line 3 */
          {
              System.out.println("Class A"); 
          } 
          public static void main(String[] args) 
          { 
              new A(); 
          } 
      }
      

    • Options
    • A. Class A
    • B. Compilation fails.
    • C. An exception is thrown at line 3.
    • D. The code executes with no output.
    • Discuss
    • 2. What will be the output of the program?
      class Test 
      {
          public static void main(String [] args) 
          {
              Test p = new Test();
              p.start();
          }
      
          void start() 
          {
              boolean b1 = false;
              boolean b2 = fix(b1);
              System.out.println(b1 + " " + b2);
          }
      
          boolean fix(boolean b1) 
          {
              b1 = true;
              return b1;
          }
      }
      

    • Options
    • A. true true
    • B. false true
    • C. true false
    • D. false false
    • Discuss
    • 3. What will be the output of the program?
      class Test 
      {
          static int s;
          public static void main(String [] args) 
          {
              Test p = new Test();
              p.start();
              System.out.println(s);
          }
      
          void start() 
          {
              int x = 7;
              twice(x);
              System.out.print(x + " ");
          }
      
          void twice(int x) 
          {
              x = x*2;
              s = x;
          }
      }
      

    • Options
    • A. 7 7
    • B. 7 14
    • C. 14 0
    • D. 14 14
    • Discuss
    • 4. You want a class to have access to members of another class in the same package. Which is the most restrictive access that accomplishes this objective?

    • Options
    • A. public
    • B. private
    • C. protected
    • D. default access
    • Discuss
    • 5. What will be the output of the program?
      class Super
      { 
          public int i = 0; 
      
          public Super(String text) /* Line 4 */
          {
              i = 1; 
          } 
      } 
      
      class Sub extends Super
      {
          public Sub(String text)
          {
              i = 2; 
          } 
      
          public static void main(String args[])
          {
              Sub sub = new Sub("Hello"); 
              System.out.println(sub.i); 
          } 
      }
      

    • Options
    • A. 0
    • B. 1
    • C. 2
    • D. Compilation fails.
    • Discuss
    • 6. What will be the output of the program (in jdk1.6 or above)?
      public class BoolTest 
      {
          public static void main(String [] args) 
          {
              Boolean b1 = new Boolean("false");
              boolean b2;
              b2 = b1.booleanValue();
              if (!b2) 
              {
                  b2 = true;
                  System.out.print("x ");
              }
              if (b1 & b2) /* Line 13 */
              {
                  System.out.print("y ");
              }
              System.out.println("z");
          }
      }
      

    • Options
    • A. z
    • B. x z