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 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

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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 these method of Thread class is used to find out the priority given to a thread?

get()	ThreadPriority()
getPriority()	getThreadPriority()

C

In the following example, which class must be abstract:

abstract class X implements Y {
  // implements all but one method of Y
}

class XX extends X {
  // implements the remaining method in Y
}

Class x	Class xx
Both	None of the above

A

What will be the content of array variable table after executing the following code?

for(int i = 0; i < 3; i + +)
for(int j = 0; j < 3; j + +)
if(j = i) table[i][j] = 1;
else table[i][j] = 0;

0 0 0 0 0 0 0 0 0	1 0 0 1 1 0 1 1 1
1 0 0 0 1 0 0 0 1	0 0 1 0 1 0 1 0 0

C

Which of these interface is not a part of Java?s collection framework?

List	Set
SortedMap	SortedList

D

SortedList is not a part of collection framework.

Which of these keywords is used by a class to use an interface defined previously?

import	Import
implememnts	Implememnts

C

Which of these method wakes up all the threads?

wakeAll()	notify()
start()	notifyAll()

D

What is the output of this program?

 class newthread extends Thread {
 Thread t;
 String name;
 newthread(String threadname) {
     name = threadname;
     t = new Thread(this,name);
     t.start();
 }
 public void run() {
        }
 
    }
    class multithreaded_programing {
        public static void main(String args[]) {
     newthread obj1 =   new newthread("one");
     newthread obj2 =  new newthread("two");
            try {
                 System.out.print(obj1.t.equals(obj2.t));
            }
            catch(Exception e) {
     System.out.print("Main thread interrupted");
            }
        }
    }

true	false

B

Which of these is a super class of all exceptional type classes?

String	RuntimeExceptions
Throwable	Cachable

C

What is the value stored in x in following lines of code? int x, y, z; x = 0; y = 1; x = y = z = 8;

0	1
9	8

D

Which of these is correct way of inheriting class A by class B?

class B + class A {}	class B inherits class A {}
class B extends A {}	class B extends class A {}

C

Finish Test

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

What is the output of this program?

 class box {
        int width;
        int height;
        int length;
        int volume;
        box() {
            width = 5;
            height = 5;
            length = 6;
        }
        void volume() {
             volume = width*height*length;
        } 
    }    
    class constructor_output {
        public static void main(String args[])
        {
            box obj = new box();
            obj.volume();
            System.out.println(obj.volume);        } 
        }
   }

100	150
200	250

B

Which of these have highest precedence?

()	++
*	>>

A

What is the output of this program?

class operators {
        public static void main(String args[]) 
        {    
             int x = 8;
             System.out.println(++x * 3 + " " + x);
        } 
    }

24 8	25 9
27 4	27 9

D

Which of the following operators can operate on a boolean variable? 1. && 2. == 3. ?: 4. +=

3 & 2	1 & 4
1, 2 & 4	1, 2 & 3

D

Given the code String s1 = "yes"; String s2 = "yes"; String s3 = new String(s1); Which of the following would equate to true? (A) s1 == s2 (B) s1 = s2 (C) s3 == s1 (D) s1.equals(s2) (E) s3.equals(s1)

(A), (C) & (E)	(A), (B) & (C)
(A), (D) & (E)	(D) & (E)

C

Which of these lines will give an error line 1 :int a=1; line 2 :float f=2; line 3 :double d=2.9;

line 1	line 2
line 3	none of these

D

no error since float can take integer value

What is the output of this program?

class equality {
        int x;
        int y;
        boolean isequal() {
            return(x == y);  
        } 
    }    
    class Output {
        public static void main(String args[])
        {
            equality obj = new equality();
            obj.x = 5;
            obj.y = 5;
            System.out.println(obj.isequal);        } 
    }

True	False
0	1

A

What is the output of this program?

 class A {
        int i;
        void display() {
            System.out.println(i);
        }
    }    
    class B extends A {
        int j;
        void display() {
            System.out.println(j);
        }
    }    
    class method_overriding {
        public static void main(String args[])
        {
            B obj = new B();
            obj.i=1;
            obj.j=2;   
            obj.display();     
        }
   }

0	1
2	Compilation Error

C

What is the output of this program?

interface calculate {
        int VAR = 0;
        void cal(int item);
    }
    class display implements calculate {
        int x;
        void cal(int item) {
            if (item < 2)
                x = VAR;
            else
                x = item * item;            
        }
    }
    class interfaces {
        public static void main(String args[]) {
            display arr[] = new display[3];
            arr[0].cal(0);    
            arr[1].cal(1);
            arr[2].cal(2);
            System.out.print(arr[0].x + " " + arr[1].x + " " + arr[2].x);
        }
    }

0 1 2	0 2 4
0 0 4	0 1 4

C

 class A {
        int i;
        void display() {
            System.out.println(i);
        }
    }    
    class B extends A {
        int j;
        void display() {
            System.out.println(j);
        }
    }    
    class inheritance_demo {
        public static void main(String args[])
        {
            B obj = new B();
            obj.i=1;
            obj.j=2;   
            obj.display();     
        }
   }

0	1
2	3

C

This is a case of method overriding or dynamic polymorphism. Here the method display of class A gets overridden by the display method of class B. Thus when the call for display method is made, method of class B gets executed.

Finish Test

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

What is the output of this program?

class exception_handling {
        public static void main(String args[]) {
            try {
                int i, sum;
                sum = 10;
                for (i = -1; i < 3 ;++i)
                    sum = (sum / i);
            }
            catch(ArithmeticException e) {
         System.out.print("0");         
            } 
            System.out.print(sum);
        }
    }

0	05
Compilation Error	Runtime Error

B

What is the output of this program?

import java.util.*;
    class vector {
        public static void main(String args[]) {
            Vector obj = new Vector(4,2);
            obj.addElement(new Integer(3));
            obj.addElement(new Integer(2));
            obj.addElement(new Integer(5));
            obj.removeAll(obj);
            System.out.println(obj.isEmpty());
        }
    }

0	1
True	False

C

firstly elements 3, 2, 5 are entered in the vector obj, but when obj.removeAll(obj); is executed all the elements are deleted and vector is empty, hence obj.isEmpty() returns true. Output: $ javac vector.java $ java vector true

Which of these method of class String is used to compare two String objects for their equality?

equals()	Equals()
isequal()	Isequal()

A

Which of these handles the exception when no catch is used?

Default handler	throw handler
finally	Java run time system

A

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

finalize	delete
constructor	class

C

What is Collection in Java?

A group of objects	A group of classes
A group of interfaces	None of the mentioned

A

A collection is a group of objects, it is similar to String Template Library (STL) of C++ programming language.

Which of these statements are incorrect?

Equal to operator has least precedence.	Brackets () have highest precedence.
Division operator, /, has higher precedence than multiplication operator.	Addition operator, +, and subtraction operator have equal precedence

C

Which of these method of String class is used to obtain character at specified index?

char()	Charat()
charat()	charAt()

D

What is synchronization in reference to a thread?

Its a process of handling situations when two or more threads need access to a shared resource.	Its a process by which many thread are able to access same shared resource simultaneously.
Its a process by which a method is able to access many different threads simultaneously.	Its a method that allow to many threads to access any information the require.

A

What is the output of this program?

class ternary_operator {
        public static void main(String args[]) 
        {        
             int x = 3;
             int y = ~ x;
             int z;
             z = x > y ? x : y;
             System.out.print(z);
        } 
    }

0	1
3	-4

C

Finish Test

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 method is used to avoid polling in Java?

wait()	notify()
notifyAll()	All of the mentioned

D

What is the output of this program?

class exception_handling {
        public static void main(String args[]) {
            try {
                int a, b;
                b = 0;
                a = 5 / b;
                System.out.print("A");
            }
            catch(ArithmeticException e) {
         System.out.print("B");         
            }
        }
    }

A	B
Compilation Error	Runtime Error

B

Which of these access specifier must be used for class so that it can be inherited by another sub class?

public	private
both a & b	None of the mentioned

A

what will be the output int i=10; System.out.println(i++);

9	10
11	12

B

i++ will first use the value and then increment it by one.

What is the output of this program?

 class Output {
        public static void main(String args[]) 
        {    
             boolean a = true;
             boolean b = false;
             boolean c = a ^ b;
             System.out.println(!b);
        } 
    }

true	false
0	1

A

What is the priority of the thread in output of this program?

  class multithreaded_programing {
        public static void main(String args[]) {
            Thread t = Thread.currentThread();
            t.setName("New Thread");
            System.out.println(t.getName());        
        }
    }

main	Thread
New Thread	Thread[New Thread,5,main]

C

Which of the folowing stements are incorrect?

Default constructor is called at the time of declaration of the object if a constructor has not been defined.	Constructor can be parameterized.
finalize() method is called when a object goes out of scope and is no longer needed.	finalize() method must be declared protected.

C

Which of these class is used to make a thread?

String	System
Thread	Runnable

C

Which of these interface is not a part of Java?s collection framework?

List	Set
SortedMap	SortedList

D

What is the value returned by unction compareTo() if the invoking string is less than the string compared?

zero	value less than zero
value greater than zero	None of the mentioned

B

Finish Test

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 interface is implemented by Thread class?

Runnable	Connections
Set	MapConnections

A

What is the output of this program?

class area {
        int width;
        int length;
        int area;
        void area(int width, int length) {
            this.width = width;
            this.length = length;
        }
 
    }    
    class Output {
        public static void main(String args[])
        {
            area obj = new area();
            obj.area(5 , 6);
            System.out.println(obj.length + " " + obj.width);        
        } 
    }

0 0	5 5
5 6	6 5

D

What should be expression1 evaluate to in using ternary operator as in this line? expression1 ? expression2 : expression3

Integer	Floating ? point numbers
Boolean	None of the mentioned

C

Which of these interface handle sequences?

Set	List
Comparator	Collection

B

Which of these is an incorrect form of using method max() to obtain maximum element?

max(Collection c)	max(Collection c, Comparator comp)
max(Comparator comp)	max(List c)

C

What is the output of this program?

class string_class {
        public static void main(String args[])
        {
            String obj = "hello";
            String obj1 = "world";   
            String obj2 = obj;
            obj2 = " world";
            System.out.println(obj + " " + obj2);
        }
    }

hello hello	world world
hello world	world hello

C

Which of these operators can be used to get run time information about an object?

getInfo	Info
instanceof	getinfoof

C

Which of these keywords is used to make a class?

class	struct
int	None of the mentioned

A

Which of these method of class String is used to check weather a given object starts with a particular string literal?

startsWith()	endsWith()
Starts()	ends()

A

What is the output of this program?

 class output {
        public static void main(String args[])
        {
             String chars[] = {"a", "b", "c", "a", "c"};
             for (int i = 0; i < chars.length; ++i)
                 for (int j = i + 1; j < chars.length; ++j)
                     if(chars[i].compareTo(chars[j]) == 0)
                         System.out.print(chars[j]); 
        }
   }

ac	ca
ab	ba

A

Finish Test

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 the folowing stements are incorrect?

Default constructor is called at the time of declaration of the object if a constructor has not been defined.	Constructor can be parameterized.
finalize() method is called when a object goes out of scope and is no longer needed.	finalize() method must be declared protected.

C

finalize() method is called just prior to garbage collection. it is not called when object goes out of scope.

Which of these operators is used to allocate memory for an object?

malloc	alloc
new	give

C

What is the return type of Constructors?

int	float
void	None of the mentioned

D

Which of these operators can skip evaluating right hand operand?

!	|
&	&&

D

Which of these keywords is used to manually throw an exception?

try	finally
throw	catch

C

Which of these class is used to make a thread?

String	System
Thread	Runnable

C

What is the output of this program?

class box {
        int width;
        int height;
        int length;
    } 
    class mainclass {
        public static void main(String args[]) 
        {        
            box obj = new box();
            System.out.println(obj);
        } 
    }

0	1
Runtime error	Garbage value

D

Which powerful construct is used to solve the problem of multiple inheritance in abstract class

Pointers	Interfaces
Abstract superclass	None of the above

B

Which of these is an invalid declaration of char line 1 :char c1='A'; line 2 :char c2=25; line 3 :char c3=2.9;

line 1	line 2
line 3	line 2 & line 3

C

line 3 will give an error since it can not take decimal values

Which of these interface is implemented by Thread class?

Runnable	Connections
Set	MapConnections

A

Finish Test

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 the following statements are incorrect?

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

D

What is the output of this program?

 interface calculate {
        void cal(int item);
    }
    class display implements calculate {
        int x;
        void cal(int item) {
            x = item * item;            
        }
    }
    class interfaces {
        public static void main(String args[]) {
            display arr = new display;
            arr.x = 0;      
            arr.cal(2);
            System.out.print(arr.x);
        }
    }

0	2
4	6

C

What is the output of this program?

 class A {
        public int i;
        public int j;
        A() {
            i = 1;
            j = 2;
 }
    }    
    class B extends A {
        int a;
        B() {
            super(ob);
        } 
    }    
    class super_use {
        public static void main(String args[])
        {
            B obj = new B();
            System.out.println(obj.i + " " + obj.j)     
        }
   }

1 2	2 1
Runtime Error	Compilation Error

A

Which of the following package stores all the standard java classes?

lang	java
util	java.packages

B

Which function of pre defined class Thread is used to check weather current thread being checked is still running?

Join()	isAlive()
isRunning()	Alive()

B

class Base { int x = 10; }
class Derived extends Base
{ int x = 20; }

Base b = new Base();
Derived d = new Derived ( );
Base bd = new Derived();
The statement
System.out.println(b.x + " " + d.x + " " + bd.x);

The output is:

10 20 10	10 20 20
20 10 20	20 20 10

A

What is the output of this program?

 interface calculate {
        void cal(int item);
    }
    class displayA implements calculate {
        int x;
        void cal(int item) {
            x = item * item;            
        }
    }
    class displayB implements calculate {
        int x;
        void cal(int item) {
            x = item / item;            
        }
    }
    class interfaces {
        public static void main(String args[]) {
            displayA arr1 = new displayA;
            displayB arr2 = new displayB;
            arr1.x = 0;
            arr2.x = 0;      
            arr1.cal(2);
            arr2.cal(2);
            System.out.print(arr1.x + " " + arr2.x);
        }
    }

0 0	2 2
4 1	1 4

C

What is the output of this program?

 abstract class A {
        int i;
        abstarct void display();
    }    
    class B extends A {
        int j;
        void display() {
            System.out.println(j);
        }
    }    
    class Abstract_demo {
        public static void main(String args[])
        {
            B obj = new B();
            obj.j=1;
            obj.display();    
        }
   }

0	1
2	3

C

Which function is used to perform some action when the object is to be destroyed?

delete()	finalize()
main()	None of the mentioned

B

What is the output of this program?

  class string_class {
        public static void main(String args[])
        {
            String obj = "I LIKE JAVA";   
            System.out.println(obj.length());
        }
    }

9	10
11	12

C

Finish Test

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 keyword is used by method to refer to the object that invoked it?

import	catch
abstract	this

D

The methods wait() and notify() are defined in

java.lang.String	java.lang.Runnable
java.lang.Thread	java.lang.Object

D

Which of these keywords is used to refer to member of base class from a sub class?

upper	super
this	None of the mentioned

B

What is the output of this program?

class multithreaded_programing {
        public static void main(String args[]) {
            Thread t = Thread.currentThread();
            t.setName("New Thread");
            System.out.println(t);        
        }
    }

Thread[5,main]	Thread[New Thread,5]
Thread[New Thread,5,main]	Thread[main,5,main]

C

What is the output of this program?

class newthread extends Thread {
 Thread t;
 String name;
 newthread(String threadname) {
     name = threadname;
     t = new Thread(this,name);
     t.start();
 }
 public void run() {
        }
 
    }
    class multithreaded_programing {
        public static void main(String args[]) {
     newthread obj1 =   new newthread("one");
     newthread obj2 =  new newthread("two");
            try {
                obj1.t.wait(); 
                System.out.print(obj1.t.isAlive());
            }
            catch(Exception e) {
     System.out.print("Main thread interrupted");
            }
        }
    }

true	false
Main thread interrupted	None of the mentioned

C

public class Test { public void foo() { assert false; /* Line 5 */ assert false; /* Line 6 */ } public void bar() { while(true) { assert false; /* Line 12 */ } assert false; /* Line 14 */ } } What causes compilation to fail?

Line 5	Line 6
Line 12	Line 14

D

Option D is correct. Compilation fails because of an unreachable statement at line 14. It is a compile-time error if a statement cannot be executed because it is unreachable. The question is now, why is line 20 unreachable? If it is because of the assert then surely line 6 would also be unreachable. The answer must be something other than assert. Examine the following: A while statement can complete normally if and only if at least one of the following is true: - The while statement is reachable and the condition expression is not a constant expression with value true. -There is a reachable break statement that exits the while statement.

What is the output of relational operators?

Integer	Boolean
Characters	Double

B

What will be the output of the program?

public class Test 
{
    public static int y;
    public static void foo(int x) 
    {
        System.out.print("foo ");
        y = x;
    }
    public static int bar(int z) 
    {
        System.out.print("bar ");
        return y = z;
    }
    public static void main(String [] args ) 
    {
        int t = 0;
        assert t > 0 : bar(7);
        assert t > 1 : foo(8); /* Line 18 */
        System.out.println("done ");
    }
}

bar	bar done
foo done	Compilation fails

D

The foo() method returns void. It is a perfectly acceptable method, but because it returns void it cannot be used in an assert statement, so line 18 will not compile.

What is the output of this program?

class box {
        int width;
        int height;
        int length;
        int volume;
        box() {
            width = 5;
            height = 5;
            length = 6;
        }
        void volume() {
             volume = width*height*length;
        } 
    }    
    class constructor_output {
        public static void main(String args[])
        {
            box obj = new box();
            obj.volume();
            System.out.println(obj.volume);        } 
        }
   }

100	150
200	250

B

What is the output of this program?

 class Relational_operator {
        public static void main(String args[])
        {
            int var1 = 5; 
            int var2 = 6;
            System.out.print(var1 > var2);
        } 
    }

0	1
false	true

C

Finish Test

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 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

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

What is the output of this program?

class access{
        public int x;
  private int y;
        void cal(int a, int b){
            x =  a + 1;
            y =  b;
        }   
        void print() {
            system.out.println(" " + y);     
        } 
    }   
    class access_specifier {
        public static void main(String args[])
        {
            access obj = new access();   
            obj.cal(2, 3);
            System.out.println(obj.x);
            obj.print();     
        }
   }

2 3	3 3
Runtime Error	Compilation Error

B

What will be the output of the program (when you run with the -ea option) ?

public class Test 
{  
    public static void main(String[] args) 
    {
        int x = 0;  
        assert (x > 0) : "assertion failed"; /* Line 6 */
        System.out.println("finished"); 
    } 
}
   

finished	Compilation fails.
An AssertionError is thrown.	An AssertionError is thrown and finished is output.

C

An assertion Error is thrown as normal giving the output "assertion failed". The word "finished" is not printed (ensure you run with the -ea option) Assertion failures are generally labeled in the stack trace with the file and line number from which they were thrown, and also in this case with the error's detail message "assertion failed". The detail message is supplied by the assert statement in line 6.

What is the correct format of declaration of abstract class

class abstract clsName { // body of class }	abstract class clsName; { // body of class }
abstract class clsName { // body of class }	None of the above

C

By which method a class can be abstracted

Private	Public
Protected	All of the above

B

Which of these methods is used to compare a specific region inside a string with another specific region in another string?

regionMatch()	match()
RegionMatches()	regionMatches()

D

What is the output of this program?

class bool_operator {
        public static void main(String args[]) 
        {    
             boolean a = true;
             boolean b = !true;
             boolean c = a | b;
       boolean d = a & b;
             boolean e = d ? b : c;
             System.out.println(d + " " + e);
        } 
    }

truefalse	falsetrue
truetrue	falsefalse

B

Which of these keywords must be used to handle the exception thrown by try block in some rational manner?

try	finally
throw	catch

D

Which of these keywords must be used to monitor for exceptions?

try	finally
throw	catch

A

Which of interface contains all the methods used for handling thread related operations in Java?

Runnable interface	ThreadHandling interface
Math interface	System interface

B

Which of the following classes are available in the java.lang package? (A) Stack (B) Object (C) Math (D) Random (E) String (F) StringBuffer (G) Vector

(B), (C) & (E)	(B), (C), (E) & (F)
(B), (E) & (F)	(A), (B), (C), (E) & (F)

B

Finish Test

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

What is the output of this program?

 class newthread extends Thread {
 Thread t;
 newthread() {
     t1 = new Thread(this,"Thread_1");
     t2 = new Thread(this,"Thread_2");
     t1.start();
     t2.start();
 }
 public void run() {
     t2.setPriority(Thread.MAX_PRIORITY); 
     System.out.print(t1.equals(t2));
        }    
    }
    class multithreaded_programing {
        public static void main(String args[]) {
            new newthread();        
        }
    }

true	false
truefalse	falsefalse

D

Which of these classes is not part of Java?s collection framework?

Maps	Array
Stack	Queue

D

Queue is not a part of collection framework

Which of these statement is correct?

true and false are numeric values 1 and 0.	true and false are numeric values 0 and 1.
true is any non zero value and false is 0.	true and false are non numeric values.

D

When does a finally block get executed ?

When an exception is thrown in a try block	When the method in which finally block is present is about to return.
When an unhandled exception is thrown in a try block.	After execution has left a try catch block, no matter exception occurs or not.

D

The finally block is executed after the try catch block has completed the execution. Whether an exception occurs or not, finally block is always executed. Hence, finally block can be used to do some common cleanup under normal or exceptional conditions.

What is the output of this program?

import java.util.*;
    class vector {
        public static void main(String args[]) {
            Vector obj = new Vector(4,2);
            obj.addElement(new Integer(3));
            obj.addElement(new Integer(2));
            obj.addElement(new Integer(5));
            obj.removeAll(obj);
            System.out.println(obj.isEmpty());
        }
    }

0	1
True	False

C

firstly elements 3, 2, 5 are entered in the vector obj, but when obj.removeAll(obj); is executed all the elements are deleted and vector is empty, hence obj.isEmpty() returns true. Output: $ javac vector.java $ java vector true

Consider the following code

int number[] = new int[5];

After execution of this statement, which of the following are true? (A) number[0] is undefined (B) number[5] is undefined (C) number[4] is null (D) number[2] is 0 (E) number.length() is 5

(B), (D) & (E)	(A) & (E)
(C) & (E)	(E)

A

What is the output of this program?

class main_class {
        public static void main(String args[])
        {
            int x = 9;
            if (x == 9) { 
                int x = 8;
                System.out.println(x);
            }
        } 
    }

9	8
Compilation error	Runtime error

C

Which of these interface declares core method that all collections will have?

set	EventListner
Comparator	Collection

D

Collection interfaces defines core methods that all the collections like set, map, arrays etc will have.

What is the output of this program?

class newthread implements Runnable {
 Thread t;
        newthread() {
            t1 = new Thread(this,"Thread_1");
            t2 = new Thread(this,"Thread_2");
            t1.start();
            t2.start();
 }
 public void run() {
            t2.setPriority(Thread.MAX_PRIORITY); 
     System.out.print(t1.equals(t2));
        }    
    }
    class multithreaded_programing {
        public static void main(String args[]) {
            new newthread();        
        }
    }

true	false
truefalse	falsefalse

D

What is the output of this program?

class Output {
        public static void main(String args[]) 
        {    
             int x , y = 1;
             x = 10;
             if (x != 10 && x / 0 == 0)
                 System.out.println(y);
             else
                 System.out.println(++y);
        } 
    }

1	2
Runtime error owing to division by zero in if condition.	Unpredictable behavior of program.

B

Finish Test