jxam.txtold

exam system for all developers

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

End#

Question# 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));

Answer# 2)

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

End#

Question# 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

Answer# 3)

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

End#

Question# 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

Answer# 1)

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

End#

Question# 29)

What is the result of the following operation
System.out.println(4 | 3);

Answer# 4)

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

End#

Question# 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.

Answer# 123

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

End#

Question# 31)

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


Answer# 2)

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

End#

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

Answer# 2)

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

End#

Question# 33)

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

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

Answer# 3)

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

End#

Question# 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.

Answer# 2)

Opt# 1) Override repaint thus
public void repaint(Graphics g){ 
paint(g); 
}
Opt# 2)Override update thus
public void update(Graphics g) { 
paint(g); 
}
Opt# 3) turn off clearing with the method setClear();
Opt# 4) Remove the drawing from the paint Method and place in the calling code

End#

Question# 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); 
	} 
} 
 
Answer# 4)

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

End#

Question# 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 conditional test here {
	System.out.println("Equal"); 
	}else { 
		System.out.println("Not equal"); 
		}
	} 
}

Answer#  3

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

End#

Question# 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

Answer# 1

Opt# 1)s.setBackground(Color.pink);
Opt# 2)s.setColor(PINK);
Opt# 3)s.Background(pink);
Opt# 4)s.color=Color.pink

End#

Question# 38) 

How can you change the current working directory using 
an instance of the File class called FileName 

Answer# 4)

Opt# 1) FileName.chdir("DirName")
Opt# 2) FileName.cd("DirName")
Opt# 3) FileName.cwd("DirName");
Opt# 4) The File class does not support directly changing the current directory.

End#

Question#  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).

Answer# 1)

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

End#

Question# 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
        }
}

Answer# 3

Opt# 1) On the line After //One put  Base(10);
Opt# 2) On the line After //One put super(10);
Opt# 3) On the line After //Two put super(10);
Opt# 4) On the line After //Three put super(10);

End#

Question# 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;
        	}
}

Answer# 3

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

End#

Question# 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]);
           }
        }
}

Answer# 4

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

End#


Question# 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);
        	}
}

Answer# 1

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

End#

Question# 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);

        }

}

Answer# 3)

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

End# 

Question# 45)

What will happen when you try compiling and running this code

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;
          }
}

Answer# 1)

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

End#
Question# 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.

Answer# 1)

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

End#

Question# 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();
v.add(99);


4) Vector v = new Vector(100);
v.addElement("99");

Answer# 4)

Opt# 1)
Opt# 2)
Opt# 3)
Opt# 4)

End#

Question# 48)

You have created a simple Frame and overriden the paint method as follows

public void paint(Graphics g){
	 g.drawString("Dolly",50,10);
	}

What will be the result when you attempt to compile and run the program;

Answer# 3)

Opt# 1) The string "Dolly" will be displayed at the centre of the form
Opt# 2) An error at compilation complaining at the signature of the paint method
Opt# 3) The lower part of the word Dolly will be seen at the top of the form, with the top hidden.
Opt# 4) The string "Dolly" will be shown at the bottom of the form

End#

Question# 49)

What will be the result when you attempt to compile this program

public class Rand{
public static void main(String argv[]){
	int iRand;
	iRand = Math.random();
	System.out.println(iRand);
	}
}

Answer# 1)

Opt# 1) Compile time error referring to a cast problem
Opt# 2) A random number between 1 and 10
Opt# 3) A random number between 0 and 1
Opt# 4) A compile time error about random being an unrecognised method

End#