Test : Java_19

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.

Select Test Type

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

Time Left - minutes :seconds

Which of these packages contains abstract keyword?

java.util	java.io
java.system	java.lang

D

A subclass of an abstract class can also be abstract if

It is instantiated	The static class is declared in the parent class
It does not define all the abstract methods in the parent class	All of the above

C

What is the name of the class that is the ancestor to every other class in Java?

Object	Class
root	java

A

In Java by default all the classes extend Object class directly or indirectly. A class declaration without the extends clause, implicitly extends the object class.

Which of the following is a method having same name as that of its class?

finalize	delete
class	constructor

D

A constructor is a method that initializes an object immediately upon creation. It has the same name as that of class in which it resides

Which of these keywords is used to define interfaces in Java?

interface	Interface
intf	Intf

A

What is the output of this program?

 import java.io.*;
    class Chararrayinput {
        public static void main(String[] args) {
     String obj  = "abcdefgh";
            int length = obj.length();
            char c[] = new char[length];
            obj.getChars(0, length, c, 0);
            CharArrayReader input1 = new CharArrayReader(c);
            CharArrayReader input2 = new CharArrayReader(c, 1, 4);
            int i;
            int j;
            try {
  while((i = input1.read()) == (j = input2.read())) {
                    System.out.print((char)i);
                }
            } 
            catch (IOException e) {
                e.printStackTrace();
     }
 }
    }

abc	abcd
abcde	None of the above

D

Which of these packages contain all the collection classes?

java.lang	java.util
java.net	java.awt

B

What is the output of the following code:

abstract class Shape
{
       void display()
       {
       }   
}

class Circle extends Shape
{
       void display()
       {
              System.out.println("You are using circle class");
       }
}

class Rectangle extends Shape
{
       void display()
       {
              System.out.println("You are using rectangle class");
       }
}

class Triangle extends Shape
{
       void display()
       {
              System.out.println("You are using triangle class");
       }
}

class AbstractClassDemo
{
       public static void main(String args[])
       {
               Shape sObj = new Circle();
               sobj.display();
               
               sObj = new Rectangle();
               sobj.display();

               sObj = new Triangle();
               sobj.display();
       }
}

You are using triangle class You are using rectangle class You are using circle class	You are using rectangle class You are using circle class You are using triangle class
You are using circle class You are using triangle class You are using rectangle class	You are using circle class You are using rectangle class You are using triangle class

D

String in Java is a?

class	object
variable	character array

A

Which of these access specifiers must be used for main() method?

private	public
protected	None of the mentioned

B

main() method must be specified public as it called by Java run time system, outside of the program. If no access specifier is used then by default member is public within its own package & cannot be accessed by Java run time system.

Finish Test