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Java Test


Time : 2.00 Hrs

Part A

50*1 = 50

1)Which of the following lines will compile without warning or error.

1) float f=1.3; 2) byte b=257; 3) boolean b=null; 4) int i=10;

 

2)What will happen if you try to compile and run the following code

public class MyClass {
public static void main(String arguments[])
{
amethod(arguments);
}
public void amethod(String[] arguments)
{
System.out.println(arguments);
System.out.println(arguments[1]);
}
}
1) error Can't make static reference to void amethod.
2) error method main not correct
3) error array must include parameter
4) amethod must be declared with String

 

3)Which of the following will compile without error

1) import java.awt.*;
package Mypackage;
class Myclass {}

2) package MyPackage;
import java.awt.*;
class MyClass{}

3) /*This is a comment */
package MyPackage;
import java.awt.*;


4)A byte can be of what size

1) -128 to 127 2) (-2 power 8 )-1 to 2 power 8
3) -255 to 256 4) depends on the Java Virtual machine

5)What will be printed out if this code is run with the following command line
java myprog good morning

public class myprog{
public static void main(String argv[])

{
System.out.println(argv[2])
}

}

1)myprog
2) good
3) morning
4) Exception raised: "java.lang.ArrayIndexOutOfBoundsException: 2"

 

6)Which of the following are java reserved words

1) if 2) then 3) goto
4) while 5) case

 

7) Which of the following are legal identifiers

1) 2variable 2) variable2 3) _whatavariable
4) _3_ 5) $anothervar 6) #myvar

 

8)What will happen when you compile the following code
public class MyClass{
static int i;
public static void main(String argv[]){
System.out.println(i);
}
}

 

1) Error Variable i may not have been initialized
2) null
3) 1
4) 0


9)What will happen if you try to compile and run the following code

public class Q {
public static void main(String argv[]){
int anar[]=new int[]{1,2,3};

System.out.println(anar[1]);
}
}

1) 1
2) Error anar is referenced before it is initialized
3) 2
4) Error size of array must be defined

 

10)What will happen if you try to compile and run the following code

public class Q {
public static void main(String argv[]){
int anar[]=new int[5];

System.out.println(anar[0]);
}
}

1) Error: anar is referenced before it is initialized
2) null
3) 0
4) 5

 

11)What will be the result of attempting to compile and run the following code

abstract class MineBase {
abstract void amethod();
static int i;
}

public class Mine extends MineBase
{
public static void main(String argv[]){
int[] ar=new int[5];
for(i=0;i < ar.length;i++)
System.out.println(ar[i]);
}
}

1) a sequence of 5 0's will be printed
2) Error: ar is used before it is initialized
3) Error Mine must be declared abstract
4) IndexOutOfBoundes Error i

 

12)What will be printed out if you attempt to compile and run the following code
int i=1;
switch (i) {
case 0:
System.out.println("zero");
break;
case 1:
System.out.println("one");
case 2:
System.out.println("two");
default:
System.out.println("default");
}

1) one 2) one, default
3) one, two, default 4) default

 

13)What will be printed out if you attempt to compile and run the following code

int i=9;
switch (i) {
default:
System.out.println("default");
case 0:
System.out.println("zero");
break;
case 1:
System.out.println("one");
case 2:
System.out.println("two"); }

1) default
2) default, zero
3) error default clause not defined
4) no output displayed

 

14)Which of the following lines of code will compile without error

1) int i=0;
if(i)
{
System.out.println("Hello");
}
2) boolean b=true;
boolean b2=true;
if(b==b2)
{
System.out.println("So true");
}

3) int i=1;
int j=2;
if(i==1|| j==2)
System.out.println("OK");

4)
int i=1;
int j=2;
if(i==1 &| j==2)
System.out.println("OK");

 

15)What will be output if you try to compile and run the following code and and there is no file called Hello.txt in the current directory.

import java.io.*;
public class Mine
{
public static void main(String argv[]){

Mine m=new Mine();
System.out.println(m.amethod());
}
public int amethod()
{
try {

FileInputStream dis=new FileInputStream("Hello.txt");
}catch (FileNotFoundException fne) {
System.out.println("No such file found");
return -1;
}catch(IOException ioe) {
} finally{
System.out.println("Doing finally");
}
return 0;
}
}

1) No such file found 2) No such file found ,-1
3) No such file found, doing finally, -1 4) 0

 

16)What tags are mandatory when creating HTML to display an applet

1) name, height, width 2) code, name
3) codebase, height, width 4) code, height, width

 

17)What will happen if you attempt to compile and run the following code

1) Compile and run without error
2) Compile time Exception
3) Runtime Exception

class Base {}
class Sub extends Base {}
class Sub2 extends Base {}

public class CEx{

public static void main(String argv[]){

Base b=new Base();

Sub s=(Sub) b;

}

}

 

18)If the following HTML code is used to display the applet in the code MgAp what will be displayed at the console.

1) Error no such parameter 2) 0
3) null 4) 30

<applet code=MgAp.class height=400 width=400 parameter HowOld=30 >
</applet>

import java.applet.*;
import java.awt.*;
public class MgAp extends Applet{

public void init(){
System.out.println(getParameter("age"));
}
}

19)You are browsing the Java HTML documentation for information on the
java.awt.TextField component. You want to create Listener code to respond to focus events. The only Listener method listed is addActionListener. How do you go about finding out about Listener methods.

1) Define your own Listener interface according to the event to be tracked
2) Use the search facility in the HTML documentation for the listener needed
3) Move up the hierarchy in the HTML documentation to locate methods in base
classes
4) Subclass awt.event with the appropriate Listener method

 

20)What will be displayed when you attempt to compile and run the following code

//Code start
import java.awt.*;

public class Butt extends Frame{

public static void main(String argv[]){
Butt MyBut=new Butt();
}

Butt(){
Button HelloBut=new Button("Hello");
Button ByeBut=new Button("Bye");
add(HelloBut);
add(ByeBut);
setSize(300,300);
setVisible(true);
}
}
//Code end

1) Two buttons side by side occupying all of the frame, Hello on the left and Bye on
the right
2) One button occupying the entire frame saying Hello
3) One button occupying the entire frame saying Bye
4) Two buttons at the top of the frame one saying Hello the other saying Bye

 

21)What will be output by the following code

public class MyFor{

public static void main(String argv[]){
int i;
int j;
outer:
for (i=1;i <3;i++)
inner:
for(j=1; j<3; j++)
{
if (j==2)
continue outer;
System.out.println("Value for i=" + i + " Value for j=" +j);
}
}
}

1) Value for i=1 value for j=1
2) value for i=2 value for j=1
3) value for i=2 value for j=2
4 value for i=3 value for j=1

 

22)Where g is a graphics instance what will the following code draw on the screen.

g.fillArc(45,90,50,50,90,180);

1) An arc bounded by a box of height 45, width 90 with a centre point of 50,50, starting
at an angle of 90 degrees traversing through 180 degrees counter clockwise.

2) An arc bounded by a box of height 50, width 50, with a centre point of 45,90 starting
at an angle of 90 degrees traversing through 180 degrees clockwise.

3) An arc bounded by a box of height 50, width 50, with a top left at coordinates of 45,
90, starting at 90 degrees and traversing through 180 degrees counter clockwise.

4) An arc starting at 45 degrees, traversing through 90 degrees clockwise bounded by a
box of height 50, width 50 with a centre point of 90, 180.

23)Which methods would it be legal to insert after the comment //XX

class Base{
public void amethod(int i) {
}

}
public class Scope extends Base{

public static void main(String argv[]){

}
//XX }

1) void amethod(int i) throws Exception {}
2) void amethod(long i)throws Exception {}
3) void amethod(long i){}
4) public void amethod(int i) throws Exception {}

24)Which of the following will output -4.0

1) System.out.println(Math.floor(-4.7));
2) System.out.println(Math.round(-4.7));
3) System.out.println(Math.ceil(-4.7));
4) System.out.println(Math.Min(-4.7));

 

25)What will happen if you attempt to compile and run the following code

Integer ten=Integer(10);
Long nine=new Long (9);

System.out.println(ten + nine);
int i=1;

System.out.println(i + ten);

 

1) 19 followed by 20
2) 19 followed by 11
3) Error: Cant convert java lang Integer
4) 10 followed by 1

26)If you run the code below, what gets printed out

String s=new String("Bicycle");
int iBegin=1;
char iEnd=3;
System.out.println(s.substring(iBegin,iEnd));

  1. Bic
    2) ic
    3) icy
    4) error: no method matching substring(int,char)

 

27)If you wanted to find out where the position of the letter v (ie return 2) in the string s containing "Java", what code could you use

1) mid(2,s); 2) charAt(2);
3) s.indexOf('v'); 4) indexOf(s,'v');

 

28)Given the following declarations
String s1=new String("Hello")
String s2=new String("there");
String s3=new String();

Which of the following are legal operations

1) s3=s1 + s2;
2) s3=s1-s2;
3) s3=s1 & s2
4) s3=s1 && s2

29)What is the result of the following operation

System.out.println(4 | 3);

1) 6 2) 0 3) 1 4) 7

 

30)public class MyClass1 {

public static void main(String argv[]){ }

/*Modifier at XX */ class MyInner {}

}

What modifiers would be legal at XX in the above code.

1) public
2) private
3) static
4) friend

 

31)How would you go about opening an image file called MyPicture.jpg

1) Graphics.getGraphics("MyPicture.jpg");
2) Image image=Toolkit.getDefaultToolkit().getImage("MyPicture.jpg");
3) Graphics.openImage("MyPicture");
4) Image m=new Image("MyPicture");

32)An Applet has its Layout Manager set to the default of FlowLayout. What code would be correct to change to another Layout Manager.

1) setLayout(new GridLayout());
2) setLayout(new GridLayout(2,2));
3) setGridLayout(2,2,))
4) setBorderLayout();

33)What will happen when you attempt to compile and run the following code.

1) It will compile and the run method will print out the increasing value of i.
2) It will compile and calling start will print out the increasing value of i.
3) The code will cause an error at compile time.
4) Compilation will cause an error because while cannot take a parameter of true.

class Background implements Runnable{
int i=0;
public int run(){
while(true){
i++;
System.out.println("i="+i);
}
}
}

34)You have created an applet that draws lines. You have overriden the paint operation and used the graphics drawLine method, and increase one of its parameters to multiple lines across the screen. When you first test the applet you find that the news lines are redrawn, but the old lines are erased. How can you modify your code to allow the old lines to stay on the screen instead of being cleared.

  1. Override repaint thus

public void repaint(Graphics g){
paint(g);
}

2)Override update thus

public void update(Graphics g) {
paint(g);
}

3) turn off clearing with the method setClear();

4) Remove the drawing from the paint Method and place in the calling code

 

35)What will be the result when you attempt to compile and run the following code.

public class Conv{

public static void main(String argv[]){
Conv c=new Conv();
String s=new String("ello");
c.amethod(s);
}
public void amethod(String s){
char c='H';
c+=s;
System.out.println(c);
}
}

 

1) Compilation and output the string "Hello"
2) Compilation and output the string "ello"
3) Compilation and output the string elloH
4) Compile time error

36)Given the following code what test would you need to put in the comment line

//place test here

to result in an output of

Equal

public class EqTest{
public static void main(String argv[]){
EqTest e=new EqTest();
}

EqTest(){
String s="Java";
String s2="java";
//place test here {

System.out.println("Equal");
}else
{
System.out.println("Not equal");
}

}
}

1) if(s==s2)
2) if(s.equals(s2)
3) if(s.equalsIgnoreCase(s2))
4)if(s.noCaseMatch(s2))

37)Given the following code
import java.awt.*;
public class SetF extends Frame{
public static void main(String argv[]){
SetF s = new SetF();
s.setSize(300,200);
s.setVisible(true);
}
}
How could you set the frame surface color to pink

1)s.setBackground(Color.pink);
1)s.setColor(PINK);
2)s.Background(pink);
3)s.color=Color.pink

 

38)How can you change the current working directory using an instance of the File class called FileName
1) FileName.chdir("DirName")
2) FileName.cd("DirName")
3) FileName.cwd("DirName");
4) The File class does not support directly changing the current directory.

 

39)If you create a TextField with a constructor to set it to occupy 5 columns, what difference will it make if you use it with a proportional font (ie Times Roman) or a fixed pitch typewriter style font (Courier).

1)With a fixed font you will see 5 characters, with a proportional it will depend on the width of the characters
2)With a fixed font you will see 5 characters,with a proportional it will cause the field to expand to fit the text
3)The columns setting does not affect the number of characters displayed
4)Both will show exactly 5 characeters

 

40)Given the following code how could you invoke the Base constructor that will print out the string "base constructor";

class Base{
        Base(int i){
        System.out.println("base constructor");
        }
        Base(){
        }
}
public class Sup extends Base{
        public static void main(String argv[]){
	     Sup s= new Sup();
        //One
        }
        Sup()
        {	    //Two
        }
        public void derived()
        {	    //Three
        }
}
1) On the line After //One put  Base(10);
2) On the line After //One put super(10);
3) On the line After //Two put super(10);
4) On the line After //Three put super(10);

41)Given the following code what will be output

public class Pass{
static int j=20;
public static void main(String argv[]){
        int i=10;
        Pass p = new Pass();
        p.amethod(i);
        System.out.println(i);
        System.out.println(j);
        }
        public void amethod(int x){
        x=x*2;
        j=j*2;
        }
}

1) Error: amethod parameter does not match variable
2) 20 and 40
3) 10 and 40
4) 10, and 20

 

42)What code placed after the comment //For loop would populate every element of the array ia[] with values of the variable i.

public class Lin{

public static void main(String argv[]){
        Lin l = new Lin();
        l.amethod(); 
        }
        public void amethod(){
        int ia[] = new int[4];
			//Start For loop        
			{
           ia[i]=i;
           System.out.println(ia[i]);
           }
        }
}

1) for(int i = 0; i < ia.length(); i++)
2) for (int i=0; i< ia.length(); i++)
3) for(int i = 1; i < 4; i++)
4) for(int i=0; i< ia.length;i++)


43) What will be the result when you try to compile and run the following code

private class Base{
Base(){
     int i = 100;     
     System.out.println(i);
     }
}
public class Pri extends Base{
static int i = 200;
public static void main(String argv[]){
        Pri p = new Pri();
        System.out.println(i);
        }
}

1) Error at compile time
2) 200
3) 100 followed by 200
4) 100


44)What will the following code print out

public class Oct{
public static void main(String argv[]){
        Oct o = new Oct();
        o.amethod();
        }
        public void amethod(){
        int oi= 012;
        System.out.println(oi);
        }
}

1)12
2)012
3)10
4)10.0

 

45)What will happen when you try compiling and running this code1

public class Ref{
public static void main(String argv[]){
          Ref r = new Ref();
          r.amethod(r);
          }
          public void amethod(Ref r){
          int i=99;
          multi(r);
          System.out.println(i);
          }
          public void multi(Ref r){
          r.i = r.i*2;
          }
}

1)Error at compile time
2) An output of 99
3) An output of 198
4) An error at runtime

 

46)You need to create a class that will store a unique object elements. You do not need to sort these elements but they must be unique.What interface might be most suitable to meet this need.

1)Set 2)List 3)Map 4)Vector

 

47)Which of the following is will sucessfully create an instance of the Vector class and add an element.

1)Vector v=new Vector(99);

v[1]=99;

2)Vector v=new Vector();

v.addElement(99);

3)Vector v=new Vector(99);

v.add(99);

4)Vector v=new Vector(99);

v.addElement("99");

48) In the list below, which subclass(es) of Component cannot be directly instantiated:

a) Panel
b) Dialog
c) Container
d) Frame


49) Of the five Component methods listed below, only one is also a method of the class MenuItem. Which one?

a) setVisible(boolean b)
b) setEnabled(boolean b)
c) getSize( )
d) setForeground(Color c)
e) setBackground(Color c)




50. Which of the following methods from the java.awt.Graphics class would be used to draw the outline of a rectangle with a single method call?

a) fillRect( )
b) drawRect( )
c) fillPolygon( )
d) drawPolygon( )
e) drawLine( )

 


Part B

(5*5 = 25)

51. Write a program which has two arrays , a[] with ten elements and b[] with six elements. Copy the first five elements from b to a ;

52. Write an application which has a Button, a TextField and a Checkbox in a Frame.

53. Create an Applet and draw a rectangle of width and height 100 pixels .

54. Explain the methods which are invoked automatically while loading your applet.

55. Write a program which has a Button in it. If the button is clicked it should print the message "Welcome" on the standard output.

CTS Question Paper


Author & Copyrights 2004: Narayanaswami Banukumar