IMP 50 Ques With Answers Mixed

Question 1

Question 1.

Read this piece of code carefully

if("String".toString() == "String")

System.out.println("Equal");

else

System.out.println("Not Equal");

Answers

1. the code will compile an print "Equal".

2. the code will compile an print "Not Equal".

3. the code will cause a compiler error.

Question 2.


if(" String ".trim() == "String")

System.out.println("Equal");

else

System.out.println("Not Equal");

Answers



3. the code will cause a compiler error

Question 3.

Read the code below. Will be the result of attempting to compile and run the code below.

public class AQuestion { public void method(Object o) { System.out.println("Object Verion"); }

public void method(String s) { System.out.println("String Version"); }public static void main(String args[]) { AQuestion question = new AQuestion(); question.method(null); }}Answers

1. The code does not compile.

2. The code compiles cleanly and shows "Object Version".

3. The code compiles cleanly and shows "String Version"

4. The code throws an Exception at Runtime.

Question 4.

Read the code below. Will be the result of attempting to compile and run the code below.

public class AQuestion { public void method(StringBuffer sb) { System.out.println("StringBuffer Verion"); }

public void method(String s) { System.out.println("String Version"); }public static void main(String args[]) { AQuestion question = new AQuestion(); question.method(null); }}Answers

1. The code does not compile.

2. The code compiles cleanly and shows "StringBuffer Version".

3. The code compiles cleanly and shows "String Version"

4. The code throws an Exception at Runtime.

Question 5.

Read the following code below.

public interface AQuestion { public abstract void someMethod() throws Exception; }

A Class implementing this interface should

1. Necessarily be an abstract class.

2. Should have the method public abstract void someMethod();

3. Should have the method public void someMethod() which has to throw an exception which is a subclass of java.lang.Exception.

4. Should have the method public void someMethod() which need not throw an Exception.

Question 6.

An Interface can never be private or protected.

Answers

True False

Question 7.

A Vector class in jdk 1.2

1. is public

2. is final

3. implements java.util.List

4. is serializable

5. has only One constructor

Question 8.

A String Class

1. is final

2. is public

3. is serializable

4. has a constructor which takes a StingBuffer Object as an Argument

Question 9.

public interface AQuestion { void someMethod(); }

The class which implements AQuestion

1. Should have someMethod which must necessarily be public.

2. Should have someMethod which could be "friendly" or public

3. Should have someMethod which should not throw any checked exceptions.

4. Should have someMethod which cannot be sychronized as sychronized is not in the signature of the interface defination

Question 10.

public class AQuestion {

private int i = j; private int j = 10; public static void main(String args[]) { System.out.println((new AQuestion()).i); }}

Answers

1. Compiler error complaining about access restriction of private variables of AQuestion.

2. Compiler error complaining about forward referencing.

3. No error - The output is 0;

4. No error - The output is 10;

Question 11.

public class AQuestion { private int i = giveMeJ(); private int j = 10;

private int giveMeJ() { return j; }

public static void main(String args[]) { System.out.println((new AQuestion()).i); } }

Answers

1. Compiler error complaining about access restriction of private variables of AQuestion.

2. Compiler error complaining about forward referencing.

3. No Compilation error - The output is 0;

4. No Compilation error - The output is 10;

Question 12.

public class AQuestion { public static void main(String args[]) { System.out.println("Before Try"); try { } catch(Throwable t) { System.out.println("Inside Catch"); } System.out.println("At the End"); } }

1. Compiler error complaining about the catch block, where no Throwable object can ever be thrown.

2. Compiler error - Throwable Object can not be caught, only Exceptions must be caught.

3. No compiler error. The lines "Before Try" and "At the end" are printed on the screen.

Question 13.

public class AQuestion { public static void main(String args[]) { System.out.println("Before Try"); try { } catch(java.io.IOException t) { System.out.println("Inside Catch"); } System.out.println("At the End"); } }1. Compiler error complaining about the catch block where no IOException object can ever be thrown.

2. Compiler error - IOException not found. It must be imported in the first line of the code.

3. No compiler error. The lines "Before Try" and "At the end" are printed on the screen.

Question 14.

The class java.lang.Exception

i. Is public ii. Extends Throwable iii. Implements Throwable iv. Is serializable

Question 15.


if("String".trim() == "String".trim()) System.out.println("Equal"); else System.out.println("Not Equal");

Answers




Question 16.


if( "STRING".toUpperCase() == "STRING") System.out.println("Equal"); else System.out.println("Not Equal");

Answers




Question 17.

The following lines of code

byte b = 0; b += 1;

1. results in b having the value 1.

2. causes a compiler error.

3. will require a cast (byte) before 1.

Question 18.

The following express

char c = -1;

1. will cause a compiler error as the range of character is between 0 and 2^16 - 1. Will request for an explicit cast.

2. will not cause a compiler error and c will have the value -1;

3. c will not represent any ascii character.

4. c will still be a unicode character.

Question 19.

Which of the following statements are true?

1. A method can throw an Exception

2. A method can return an Exception

Question 20.

All the wrapper classes (Integer, Boolean, Float, Short, Long, Double and Character)

1. are public

2. are serializable

3. are immutatable

4. extend java.lang.Number

5. are final

Question 31.


if("String".replace('T','t') == "String") System.out.println("Equal"); else System.out.println("Not Equal");

Answers




Question 32.


System.out.println("String".substring(0,4));

Answers

1. the code will print "Strin" on the screen.

2. the code will print "Stri" on the screen.

3. the code will cause a compiler error.

Question 33.


if("String".replace('g','G') == "String".replace('g','G')) System.out.println("Equal"); else System.out.println("Not Equal");

Answers




Question 34.

public class ADirtyOne { public static void main(String args[]) { System.out.println(Math.abs(Integer.MIN_VALUE)); } }

an attempt to compile and run the above class will

1. Cause a compiler error.

2. Cause no error and the value printed on the screen is less than zero.

3. Cause no error and the value printed on the screen is one more than Integer.MAX_VALUE

4. Will throw a runtime exception due to overflow - Integer.MAX_VALUE is less in magnitue than Integer.MIN_VALUE.

Question 35.

public class ADirtyOne { public static void main(String args[]) { System.out.println(Math.min(0.0,-0.0)); } }

An attempt to compile and run the above class will

1. Cause a compiler Error.

2. Cause no error and print the value 0.0 on the screen.

3. Cause no error and prints the value -0.0 on the screen.

Question 36.

public class Base { public void aMethod() throws ClassNotFoundException { } }public class Derived extends Base { public void aMethod() throws RuntimeException { } }Assuming that the classes are in two seperate files, compilation of the Dervied.java causes

1. A compiler error because RuntimeException is not a subclass if ClassNotFoundException.

2. No compiler error.

Question 37.

Math.round(Float.MAX_VALUE);

1. Returns Integer.MAX_VALUE.

2. Returns a closest integer to Float.MAX_VALUE;

3. Causes a compilation error.

4. Causes a runtime Exception

Question 38.

Read the code below carefully

import java.awt.*; public class TestFrame extends Frame {

Button bNorth = new Button("North"); Button bSouth = new Button("South"); Button bEast = new Button("East"); Button bWest = new Button("West"); Button bCenter = new Button("Center");

public TestFrame() { setLayout(new BorderLayout()); add(bSouth,BorderLayout.SOUTH); add(bWest,BorderLayout.WEST); add(bEast,BorderLayout.EAST); add(bNorth,BorderLayout.NORTH); add(bCenter);

setLayout(new FlowLayout());

validate(); pack(); setVisible(true); }

public static void main(String args[]) { TestFrame tf = new TestFrame(); }}

What will be the effect trying compile and run the above class?

1. Compilation error - a Layout cannot be set twice for a component.

2. Compilation error - One button is added without specifing the position in the borderLayout

3. No Compilation Error. The Buttons are arranged in a line in the order (From left to right) "North","South","West","East" and "Center".

4. No Compilation Error. The Buttons are arranged in a line in the order (From left to right) "South","West","East","North" and "Center".

5. No Compilation Error. The Buttons are arranged in the north , south, west, east and center regions, as in a borderlayout. Any further additions will follow the rules of FlowLayout manager.

Question 39.

import java.awt.*; public class TestFrame extends Frame {

Button bNorth = new Button("North"); Button bSouth = new Button("South"); Button bEast = new Button("East"); Button bWest = new Button("West"); Button bCenter = new Button("Center");

public TestFrame() { setLayout(new FlowLayout()); add(bNorth); add(bSouth); add(bWest); add(bEast); add(bCenter);

setLayout(new BorderLayout()); validate(); setSize(300,300); setVisible(true); }

public static void main(String args[]) { TestFrame tf = new TestFrame(); } }

Attemping to compile and run the above code

1. Will cause a compilation error - a Layout cannot be set after a component has been added with a preset Layout Manager.

2. Will cause a Runtime Exception - a Layout cannot be set after a component has been added with a preset Layout Manager.

3. Will compile cleanly and throw no runtime Exception. Only the button with label "Center" is visible and occupies the whole screen.

4. Will compile cleanly an throw no runtime Exception. All the buttons are arranged in a single line. Any other component added in future will follow the rules of the BorderLayout Manager.

5. Will compile and run cleanly, but no component is visible.

6. Will compile cleanly and throw no runtime Exception. The buttons are arranged as listed below

Button LabelPosition

CenterCenter

NorthNorth

SouthSouth

EastEast

WestWest

Question 40.

A frame uses BorderLayout Management and has components added to all the regions. One resizing the Frame Some space becomes available. The space is alloted to the regions, in which Order of preference?

1. North , South, West, East and then Center.

2. North , West, South, Center and then Center.

3. Center, East, West, South and then North.

4. West, Center, South, North and then East.

Question 41.

Read the following piece of code carefully.

import java.awt.*;

public class TestFrame extends Frame { Button firstOne = new Button("One"); Button secondOne = new Button("Two");

public TestFrame() { add(firstOne,BorderLayout.NORTH); add(secondOne,BorderLayout.NORTH);

setSize(400,400); setVisible(true); } public static void main(String args[]) { TestFrame tf = new TestFrame(); } }

An Attempt to compile and run the above piece of code

1. Causes compilation error - a component cannot be added to region which is already occupied by another component.

2. Causes Runtime Exception - a component cannot be added to region which is already occupied by another component.

3. Neither i or ii. The Frame comes up and only the button with label "Two" occupies the entire North region of the Frame.

4. Addition of secondOne causes firstOne to be removed from the container.

5. Addition of the secondOne causes the firstOne to be hidden in the container.

Question 42.

import java.awt.*;

public class TestFrame extends Frame { public TestFrame() { Button one = new Button("One"); Button two = new Button("Two"); Button three = new Button("Three"); setLayout(new FlowLayout());

add(one); add(two); add(three);

two.setVisible(false);

setSize(1000,1000); setVisible(true); validate(); } public static void main(String args[]) { TestFrame tf = new TestFrame(); } }1. If the above code runs, the buttons - one and three are laid out in a single row from left to right with a gap in between .

2. If the above code runs, the buttons - one and three are laid out in a single row from left to right with no gap in between.

3. Code does not compile - a component can not be hidden after being added to a container.

4. Code gets compiled successfully but throws runtime Exception - a component can not be hidden after being added to a container.

Question 43.

Read the code below carefully.

import java.awt.*;

public class TestFrame extends Frame { public TestFrame() { setLayout(new GridLayout(2,1)); for(int i = 1 ; i

Date post:	13-Sep-2015
Category:	Documents
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IMP 50 Ques With Answers Mixed

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