jxam.txt

exam system for all developers

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#

Question# 50) Given the following code

import java.io.*;

public class Th{
	public static void main(String argv[]){
	Th t = new Th();
	t.amethod();
	}
	public void amethod(){
		try{
		ioCall();
		}catch(IOException ioe){}
	}
	
}
What code is would be most likely for the body of the ioCall method

1) public void ioCall ()throws IOException{
	DataInputStream din = new DataInputStream(System.in);
	din.readChar();
	}
2) public void ioCall ()throw IOException{
	DataInputStream din = new DataInputStream(System.in);
	din.readChar();
	}
3) public void ioCall (){
	DataInputStream din = new DataInputStream(System.in);
	din.readChar();
	}
4) public void ioCall throws IOException(){	
   DataInputStream din = new DataInputStream(System.in);
	din.readChar();
	}

Answer# 1

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

End#

Question# 51)What will happen when you compile and run the following code?

public class Scope{
private int i;
public static void main(String argv[]){
         Scope s = new Scope();
         s.amethod();
        }//End of main
        public static void amethod(){
          System.out.println(i);
        }//end of amethod
}//End of class

Answer# 3)

Opt# 1) A value of 0 will be printed out
Opt# 2) Nothing will be printed out
Opt# 3) A compile time error 
Opt# 4) A compile time error complaining of the scope of the variable i

End#

Question# 52)

You want to lay out a set of buttons horizontally but with more space between the first button and the rest. 
You are going to use the GridBagLayout manager to control the way the buttons are set out. How will you modify 
the way the GridBagLayout acts in order to change the spacing around the first button?

1) Create an instance of the GridBagConstraints class, call the weightx() method and then 
pass the GridBagConstraints instance with the component to the setConstraints method 
of the GridBagLayout class.

2) Create an instance of the GridBagConstraints class, set the weightx field and 
then pass the GridBagConstraints instance with the component to the setConstraints method of 
the GridBagLayout class.

3) Create an instance of the GridBagLayout class, set the weightx field and then call the setConstraints 
method of the GridBagLayoutClass with the component as a parameter.

4) Create an instance of the GridBagLayout class, call the setWeightx() method and then pass the 
GridBagConstraints instance with the component to the setConstraints method of the GridBagLayout 
class.

Answer# 2)

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

End#

Question# 53)

Which of the following can you perform using the File class?

Answer# 23

Opt# 1) Change the current directory
Opt# 2) Return the name of the parent directory
Opt# 3) Delete a file
Opt# 4) Find if a file contains text or binary information

End#

Question# 54)

Which of the following code fragments will compile without error

1)
public void paint(Graphics g){
  int polyX[] = {20,150,150};
  int polyY[]= {20,20,120};
  g.drawPolygon(polyX, polyY,3);
  }
2)
public void paint(Graphics g){
  int polyX[] = {20,150,150};
  int polyY[]= {20,20,120};
  g.drawPolygon(polyX, polyY);
  }
3)
public void paint(Graphics g){
  int polyX[3] = {20,150,150};
  int polyY[3]= {20,20,120};
  g.drawPolygon(polyX, polyY,3);
  }
4)
public void paint(Graphics g){
  int polyX[] = {20,150,150};
  int polyY[]= {20,20,120};
  drawPolygon(polyX, polyY);
  }

Answer# 1)

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

End#

Question# 55)

You are concerned about that your program may attempt to use more memory than is available. 
To avoid this situation you want to ensure that the Java Virtual Machine will run its 
garbage collection just before you start a complex routine. What can you do to be 
certain that garbage collection will run when you want .

Answer# 1)

Opt# 1) You cannot be certain when garbage collection will run
Opt# 2) Use the Runtime.gc() method to force garbage collection
Opt# 3) Ensure that all the variables you require to be garbage collected are set to null
Opt# 4) Use the System.gc() method to force garbage collection

End#

Question# 56)

You are using the GridBagLayout manager to place a series of buttons on a Frame. You want to make the size of 
one of the buttons bigger than the text it contains. Which of the following will allow you to do that?

Answer# 4)

Opt# 1) The GridBagLayout manager does not allow you to do this
Opt# 2) The setFill method of the GridBagLayout class
Opt# 3) The setFill method of the GridBagConstraints class
Opt# 4) The fill field of the GridBagConstraints class

End#

Question# 57)

Which of the following most closley describes a bitset collection

Answer# 4)

Opt# 1) A class that contans groups of unique sequence of bits
Opt# 2) A method for flipping individual bits in instance of a primitive type
Opt# 3) An array of boolean primitives that indicate zeros or ones
Opt# 4) A collection for storing bits as on-off information, like a verctor of bits

End#

Question# 58)

You have these files in the same directory. What will happen when you attempt to compile and run File1 if you have not already compiled File2.
//File 1
package Base;
class Base{
        protected void amethod(){
                System.out.println("amethod");
        }//End of amethod
}//End of class base
//File2
package Class1;

public class Class1{

public static void main(String argv[]){
                Base b = new Base();
                b.amethod();
               }//End of main
}//End of Class1

Answer# 4)

Opt# 1) Compile Error: Methods in Base not found
Opt# 2) Compile Error: Unable to access protected method in base class
Opt# 3) Compilation followd by the output "amethod"
Opt# 4)Compile error: Superclass Class1.Base of class Class1.Class1 not found

End#

Question# 59)

What will happen when you attempt to compile and run the following code
class Base{
private void amethod(int iBase){
        System.out.println("Base.amethod");
        }
}

class Over extends Base{


public static void main(String argv[]){
        Over o = new Over();
        int iBase=0;
        o.amethod(iBase);
        }
        public void amethod(int iOver){
                System.out.println("Over.amethod");
        }

}

Answer# 4)

Opt# 1) Compile time error complaining that Base.amethod is private
Opt# 2) Runtime error complaining that Base.amethod is private
Opt# 3) Output of Base.amethod
Opt# 4) Output of Over.amethod()

End#

Question# 60)

You are creating an applet with a Frame that contains buttons. You are using 
the GridBagLayout manager  and you have added Four buttons. At the moment the 
buttons apear in the centre of the frame from left to right. You want them to 
appear one on top of the other going down the screen. What is the most appropriate 
way to do this.


Answer# 1)

Opt# 1) Set the gridy value of the GridBagConstraint class to a value increasing from 1 to 4
Opt# 2) set the fill value of the GridBagConstrint class to VERTICAL
Opt# 3)) Set the ipady value of the GridBagConstraint class to a value increasing from 0 to 4
Opt# 4) Set the fill value of the GridBagLayout class to GridBag.VERTICAL

End#