Java Programming OOP Questions and Answers Set 1

Java Programming OOPs

Questions 1 to 10



1.
The default value of a static integer  variable of a class in Java is,
(a)  0                       (b)  1                       (c)  Garbage value   (d)  Null    (e)  -1.
2.
What will be printed as the output of the following program?
                  public class testincr
                  {
                  public static void main(String args[])
                  {
                     int i = 0;
                     i = i++ + i;
                     System.out.println("I = " +i);
                   }
                   }
(a)  I = 0           (b)  I = 1           (c)  I = 2                (d)  I = 3                (e)  Compile-time Error.
3.
Multiple inheritance means,
(a)   one class inheriting from more super classes
(b)   more classes inheriting from one super class
(c)   more classes inheriting from more super classes
(d)   None of the above
(e)   (a) and (b) above.
4.
Which statement is not true in java language?
(a)   A public member of a class can be accessed in all the packages.
(b)   A private member of a class cannot be accessed by the methods of the same class.
(c)   A private member of a class cannot be accessed from its derived class.
(d)   A protected member of a class can be accessed from its derived class.
(e)   None of the above.
5.
To prevent any method from overriding, we declare the method as,
(a)  static        (b)  const            (c)  final              (d)  abstract             (e)  none of the above.
6.
Which one of the following is not true?
(a)   A class containing abstract methods is called an abstract class.
(b)   Abstract methods should be implemented in the derived class.
(c)   An abstract class cannot have non-abstract methods.
(d)   A class must be qualified as ‘abstract’ class, if it contains one abstract method.
(e)   None of the above.
7.
The fields in an interface are implicitly specified as,
(a)  static only                                        (b)  protected                                        (c)  private
(d)  both static and final                         (e)  none of the above.
8.
What is the output of the following program:
                       public class testmeth
                       {
                           static int i = 1;
                           public static void main(String args[])
                            {
                                 System.out.println(i+” , “);
                                 m(i);
                                 System.out.println(i);
                            }
                            public void m(int i)
                            {
                               i += 2;                              
                            }
                       }
(a)  1 , 3                  (b)  3 , 1                  (c)  1 , 1                  (d)  1 , 0        (e)  none of the above.
9.
Which of the following is not true?
(a)   An interface can extend another interface.
(b)   A class which is implementing an interface must implement all the methods of the interface.
(c)   An interface can implement another interface.
(d)   An interface is a solution for multiple inheritance in java.
(e)   None of the above.
10.
Which of the following is true?
(a)   A finally block is executed before the catch block but after the try block.
(b)   A finally block is executed, only after the catch block is executed.
(c)   A finally block is executed whether an exception is thrown or not.
(d)   A finally block is executed, only if an exception occurs.
(e)   None of the above.

Answers


1.
Answer : (a)
Reason:  The default value of a static integer  variable of a class in Java is 0.
2.
Answer : (b)
Reason:  1
                The execution goes on like this:
                          int i = 0;    //  i becomes 0
                          i = 0 + i;  //    now, i becomes 1
                          i = 0 + 1;  //    perform addition and assign 1 to i.
3.
Answer : (a)
Reason:  Multiple inheritance means one class inheriting from more super classes.
4.
Answer : (b)
Reason:  Private members of a class can be accessed by the methods within the same class.
5.
Answer : (c)
Reason:  Final methods of the base class cannot be overridden in the derived Class.
6.
Answer : (c)
Reason:  An abstract class can contain both abstract and non-abstract methods.
7.
Answer : (d)
Reason:  The fields in an interface are implicitly specified as both static and final.
8.
Answer : (c)
Reason:  Parameter values are passed by value in the calling of a method, and  so a copy of the value is created in the method, and the original value is not affected by the method call.
9.
Answer : (c)
Reason:  An interface can extend another interface but not implement.
10.
Answer : (c)
Reason:  A finally block is executed whether an exception is thrown or not is correct.



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14 comments :

  1. I get it very helpful.keep it up.Thanks

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    Replies
    1. Tks very much for your post.

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  2. Answer of q. no. 8 is e. run it and find why .

    ReplyDelete
    Replies
    1. deepak is right, compiler returns console error

      Delete
  3. Question No. 8, Answer is not correct, The correct answer is compile time error because, the method m() is non static and you are calling without creating the instance on the main method.

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  4. Very good questions . Here are some 30 Java OOP concept interview questions, I have found immensely useful. Thanks

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  5. Question No.8 is not correct please re-check it

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