jxam.txt

exam system for all developers

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

Answer#  5

Opt# 1) float f = 1.3;
Opt# 2) char c = "a";
Opt# 3) byte b = 257;
Opt# 4) boolean b = null;
Opt# 5) int i = 10;

End#

Question# 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]);
  	}
}

Answer# 1

Opt# 1) error Can't make static reference to void amethod.
Opt# 2) error method main not correct
Opt# 3) error array must include parameter
Opt# 4) amethod must be declared with String
End#

Question# 3) Which of the following will compile without error

Answer# 23


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

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

Opt# 3) 

 /*This is a comment */
package MyPackage;
import java.awt.*;
class MyClass{}

End#


Question# 4) A byte can be of what size

Answer# 1

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

End#


Question# 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]) }
	}
}

Answer# 4

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

End#

Question# 6) Which of the following are java reserved words

Answer# 1345

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

End#
Question# 7) Which of the following are legal identifiers

Answer# 2345

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

End#
Question# 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); 
	} 
}

Answer# 4

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

End#

Question# 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]); 
	} 
}

Answer# 3

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

End#

Question# 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]); 
	} 
}

Answer# 3

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

End#


Question# 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]); 
	} 
}

Answer# 3

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

End#
Question# 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"); 
	}

Answer# 3

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


End#

Question# 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"); 
}

Answer# 2

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

End#

Question# 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");


Answer# 23

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


End#

Question# 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; 
	} 
}

Answer# 3

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

End#

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

Answer# 4) 

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

End#

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

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;
	}
}

Answer# 3) 

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


End#

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

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

iport java.applet.*; 
import java.awt.*; 
public class MgAp extends Applet{
	public void init(){ 
	System.out.println(getParameter("age")); 
	} 
} 
 
Answer# 3) 

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

End# 

Question# 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.

Answer# 3)

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

End#

Question# 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

Answer# 3) 

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


End#

Question# 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); 
		} 
		} 
}

Answer# 1 2

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

End#

Question# 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.

Answer# 3)

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

End#

Question# 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
}

Answer# 23

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

End#

Question# 24) Which of the following will output -4.0

Answer# 3

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

End#

Question# 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);

Answer# 3)

Opt# 1) 19 followed by 20 
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){