Test : Java_10

This test contains 10 questions based on Java.
Each question answered correctly awards you 1 point and each incorrect answer has a penalty of -0.25 points, no points are deducted for unattempted answers.

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You Get +1 for each correct answer and -0.25 for each incorrect answer

Time Left - minutes :seconds

Which of the following statements are false in the concept of abstract classes:

Can b instantiated	It may or may not include abstract methods
It can be subclassed	None of the above

A

Which of these is static variable defined in Collections?

EMPTY_SET	EMPTY_LIST
EMPTY_MAP	All of the mentioned

D

Which of the following statements are incorrect?

private members of class can only be accessed by other members of the class	private members of class can be inherited by a sub class, and become protected members in sub class
protected members of a class can be inherited by a sub class, and become private members of the sub class	public members of class can be accessed by any code in the program

B

What is the output of this program?

 import java.util.*;
    class Bitset {
        public static void main(String args[]) {
            BitSet obj = new BitSet(5);
            for (int i = 0; i < 5; ++i)
                obj.set(i);
            obj.clear(2);
            System.out.print(obj);
        }
    }

{0, 1, 3, 4}	{0, 1, 2, 4}
{0, 1, 2, 3, 4}	{0, 0, 0, 3, 4}

A

what will be the output int a=2; System.out.println(a<<2);

0	8
6	none of these

B

binary representation of 2 =10 now << operator will shift digits 2 places to left, therefore new number=1000 1000 =8

Which of these is used as default for a member of a class if no access specifier is used for it?

private	public
public, within its own package	protected

A

When we pass an argument by call-by-value a copy of argument is made into the formal parameter of the subroutine and changes made on parameters of subroutine have no effect on original argument, they remain the same.

Which of these is not a correct statement?

Every class containing abstract method must be declared abstract.	Abstract class defines only the structure of the class not its implementation.
Abstract class can be initiated by new operator.	Abstract class can be inherited.

C

Which of the following statements are incorrect?

String is a class.	Strings in java are mutable
Every string is an object of class String.	Java defines a peer class of String, called StringBuffer, which allows string to be altered

B

What is the output of this program?

class output {
        public static void main(String args[])
        {
            char ch;
            ch = "hello".charAt(1);
            System.out.println(ch);
        }
   }

h	e
l	o

B

Difference between == and equals method?

both behaves same	== compares the references whereas equals compares the contents
== compares the contents whereas equals compares the references	None of the above

B

== operator always compares the references of the objects and equals method compares the contents of the object.

Finish Test