Monday, February 6, 2012

SCJP model question answer page 7


61)
interface I{
final class C1{     //1  
                static int i=9;;  //2
                }
}
class C2 implements I{
 public static void main(String a[]){
                System.out.println(I.C1.i);  ///3
}
}

compile time error at line 1

compile time error at line 2

compile time error at line 3

prints 9

Runtime exception

Explanation:
interfaces classes are by default static,final. so,no compile time errors are genearated
Ans: 4


62)
class C{
public static void main(String[] args) {
  try
    {
        try
           {
               try
                 {
                   }
                 catch(RuntimeException e)
                 {
                  }
             }
           catch(Exception e)
           {
            }
             
      }
    catch(NullPointerException e)
    {
        }
     finally
    {
              System.out.println("finally");

      }
}}


Prints finally

compile time error

Runtime Exception

None of the above

Ans: 1

63)
class C {
  public static void main ( String ka [ ] ) {
          while ( false ) {
                  System.out.println ( "Value" ) ;
          }
  }
}

compile time error

prints Value infinitely

Runtime Exception

None of the above

Ans: 1


64)
class C {
            public static void main(String[] args)
            {
              System.out.println(4+5+"String");
            }
}

prints 9string

prints 45string

compile time error

Runtime exception

None of the above

Explanation:
arguments to the method are evalutated from left to right so 4+5+"string" ==> 9+string==>9string
Ans: 1


65)
class H {
  public static void main (String[] args) {
    String s1 = "HHH";
    StringBuffer sb2 = new StringBuffer(s1);
    System.out.print(sb2.equals(s1) + "," + s1.equals(sb2));
}}


Prints: false,false

Prints: true,false

Prints: false,true

Prints: true,true

None of the above

Explanation:
s1 and sb2 are pointing to different object references
Ans: 1


66)
The relationship between a class and its superclass is
has-a

is -a

None of the above
Ans: 2

67)

class A extends Thread {
  private int i;
  public void run() {i = 1;}
  public static void main(String[] args) {
    A a = new A();
    a.run();
    System.out.print(a.i);
}}
How many threads are created in this Program?

Ans: 1

Ans: 2

Ans: 3

Ans:None of the above
Explanation:
Main thread is a thread and calling run methods will not creat thread.
Ans: 1

68)
String objects once created can not be modified
true

false

Ans: 1


69)
Which of the following modifiers can be applied to a class that is not a nested class?


public

protected

private

static

Ans: 1

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