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Home ‣ Java Programming ‣ Exceptions See What Others Are Saying!
  • Question

  • At Point X on line 5, which code is necessary to make the code compile? 
    public class ExceptionTest 
{ 
    class TestException extends Exception {} 
    public void runTest() throws TestException {} 
    public void test() /* Point X */ 
    { 
        runTest(); 
    } 
}


  • Options
  • A. No code is necessary.
  • B. throws Exception
  • C. catch ( Exception e )
  • D. throws RuntimeException

  • Correct Answer
  • throws Exception 

    Explanation
    Option B is correct. This works because it DOES throw an exception if an error occurs.

    Option A is wrong. If you compile the code as given the compiler will complain:

    "unreported exception must be caught or declared to be thrown" The class extends Exception so we are forced to test for exceptions.

    Option C is wrong. The catch statement belongs in a method body not a method specification.

    Option D is wrong. TestException is a subclass of Exception therefore the test method, in this example, must throw TestException or some other class further up the Exception tree. Throwing RuntimeException is just not on as this belongs in the java.lang.RuntimeException branch (it is not a superclass of TestException). The compiler complains with the same error as in A above.

    • 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

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