Java Lab Solutions

8/6/2019 Java Lab Solutions

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// Program to calculate the Square of a number.

import java.io.*;

class Square1

{

public static void main(String args[])

{try

{

int a,s;

String line;

System.out.println("Enter the required value:");

BufferedReader d=new BufferedReader(new InputStreamReader(System.in));

line =d.readLine();

a = Integer.parseInt(line);

s = a*a;System.out.println(s);

}

catch(IOException e)

{}

}

}

//Program to print the entered number is Armstrong number or not

import java.io.*;

class Armstrong

{

public static void main(String arg[])

{

try

{

int a,b,c,e;

String line;



line =d.readLine();


b = 0;

c = 0;

e = a;

int factorial=1;

while (a != 0)

{

b = a % 10;

c = c + b * b * b;a = a / 10;

}

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if (e == c)

{

System.out.print("Armstrong Number ");

}

else

{

System.out.print("Not Armstrong");}

}


{}

}

}

// Program to calculate the Factorial of a number

import java.io.*;

class Fact{


{

try

{

int a,s;

String line;



line =d.readLine();


int factorial=1;

for (int i = a; i > 0; i--)

{

factorial = factorial * i;

}

System.out.print("factorial of " + a);System.out.print(" = " + factorial);

}


{}

}

}

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// Program to print Prime numbers from 1 to 100.

class Prime

{

public static void main(String[] args)

{

int i=1,j;

int flag=0;for (i=2;i


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// Box uses a constructor to initialize the dimensions of a box

class Box

{

double width;

double height;

double depth;

// This is the constructor for Box

Box()

{

System.out.println("Constructing Box");

width = 10;

height = 10;

depth = 10;

}

// Compute and return volumedouble volume()

{

return width * height * depth;

}

}

class BoxDemo

{


{

// declare, allocate, and initialize Box objects

Box mybox1 = new Box();

Box mybox2 = new Box();

double vol;

// Get volume of first box

vol = mybox1.volume();

System.out.println("Volume is " + vol);

// Get volume of second boxvol = mybox2.volume();


}

}

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// Here, Box uses parameterized constructor to initialize the dimensions of a box

class Box

{

double width;

double height;

double depth;

// This is the constructor for Box

Box(double w, double h, double d)

{

width = w;

height = h;

depth = d;

}

// Compute and return volume

double volume()

{return width * height * depth;

}

}

class BoxDemoParam

{


{

// declare, allocate, and initialize Box objects

Box mybox1 = new Box(10, 20, 15);

Box mybox2 = new Box(3, 6, 9);

double vol;

// Get volume of first box



// Get volume of second box


System.out.println("Volume is " + vol);}

}

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//Method Overloading and parameter passing

class Overloadtest

{

void test()

{

System.out.println("No Parameters");}

//Overload test for one integer parameter

void test(int a)

{

System.out.println("a: " + a);

}

//Overload test for two integer parameters

void test(int a, int b)

{

System.out.println("a and b: " + a + " " + b);

}//Overload test for double parameter

double test(double a)

{

System.out.println("double a: " + a);

return a*a;

}

}

class Overload

{


{

Overloadtest t = new Overloadtest();

double result;

//Call all versions of test()

t.test();

t.test(10);

t.test(10,20);

result = t.test(125.25);

System.out.println("Result of t.test(125.25): " + result);}

}

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// Using throw exception

class Throwdemo

{

static void demoproc()

{try

{

throw new NullPointerException("demo");

}

catch(NullPointerException e)

{

System.out.println("Caught inside demoproc");

throw e;

}

}

public static void main(String args[]){

try

{

demoproc();

}

catch(NullPointerException e){

System.out.println("Recaught:"+e);

}

}

}

// Using throws

class ThrowsDemo

{

static void throwsOne() throws IllegalAccessException

{

System.out.println("Inside throwOne");

throw new IllegalAccessException("Demo");

}


try

{

throwsOne();

}catch(IllegalAccessException e)

{

System.out.println("Caught" +e);

}

}

}

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// Using finally

import java.io.*;

class FinallyDemo

{

static void procA(){

try

{

System.out.println("Inside procA");

throw new RuntimeException ("Demo");

}

finally

{

System.out.println("procA's finally");

}

}

//Return from within a try block

static void procB()

{

try

{

System.out.println("Inside procB");

return;

}

finally

{

System.out.println("procB's finally");

}

}

//Execute a try block normally

static void procC()

{

try

{

System.out.println("Inside procC");}

finally

{

System.out.println("procC's finally");

}

}


{

try

{procA();

}

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catch(Exception e)

{

System.out.println("Exception caught");

}

procB();

procC();}

}

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// Using String methods

class Stringdemo

{


{

String str1="Hello everyone, great day ";String str2="World";

String str4=str1;

String str3[]= {"ONE","TWO","THREE","FOUR"};

for(int i=0 ; i


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//Program to Sort an Array of string in an Ascending order

import java.util.Arrays;

class SortString

{


{String name[] = new String[6];

name[0] = "Neeta";

name[1] = "Seeta";

name[2] = "Mohan";

name[3] = "Ashim";

name[4] = "Shama";

name[5] = "Geeta";

System.out.println("Array Before Sorting");

System.out.println("********************");

for (int i=0; i


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System.out.println("********************");

//Arrays.sort(name);

Arrays.sort(name, Collections.reverseOrder());

for (int i=0; i


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// Using Inheritance

class Info

{

protected String name="sahil";

protected String addr="9 ,vile parle (E)";}

class Info1 extends Info

{

private int age=22;

public void disp1()

{

System.out.println("name :" + name);

System.out.println("address :" + addr);System.out.println("age is :" + age);

}


{

Info1 i1= new Info1();

i1.disp1();

}

}

import java.io.*;

class books

{

protected String aut;

protected String name;

void getDet()

{

//super.getDet();

try

{BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

System.out.println("enter author name");

aut=br.readLine();

System.out.println("enter book name");

name=br.readLine();

}

catch(IOException e) {}

}

void showDet()

{//super.showDet();

System.out.println("showing book details...");

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System.out.println("===============");

System.out.println("author :" + aut);

System.out.println("bookname :" + name);

}

}

import java.io.*;

class Category extends books

{

private String catcode;

void getDet()

{

super.getDet();

try

{

BufferedReader br=new BufferedReader (new InputStreamReader(System.in));System.out.println("enter category code");

catcode=br.readLine();

}

catch(IOException e) {}

}

void showDet()

{

super.showDet();

System.out.println("showing category details...");

System.out.println("======================");

System.out.println("Category code:" + catcode);

}


{

Category c=new Category();

c.getDet();

c.showDet();

}

}

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// Interfaces

public interface Test

{

public int square(int a);

}

class Arithmetic implements Test

{

int s = 0;

public int square(int b)

{

s = b * b;

System.out.println("Inside Arithmetic class implemented method

square");

System.out.println("Square of " + b + " is " + s);

return s;}

void armeth()

{

System.out.println("Inside method of class Arithmetic");

}

}

class ToTestInt

{

public static void main(String args[]) {

System.out.println("Calling... from ToTestInt class main method");

Test t = new Arithmetic();

System.out.println("===========================");

System.out.println("Created object of test interface - reference Arithmetic class");

System.out.println("Hence Arithmetic class method square called");

System.out.println("This object cannot call armeth method of Arithmetic class");


t.square(10);


}}

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// Package

// Create a folder Pack and write the following code in this folder

package Pack;

public class Class1{

public static void greet()

{

System.out.println("Hello");

}

}

// Create a folder Subpack in a Pack folder and write the following code in this folder

package Pack.Subpack;

public class Class2 {

public static void farewell() {System.out.println("bye");

}

}

// Come out of both the folders and write the following code

// Importing Packages

import Pack.*;

import Pack.Subpack.*;

class Importer {


{

Class1.greet();

Class2.farewell();

}

}

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// Multithreading

//to illustrate creation of threads using class Thread

class MyThread extends Thread

{MyThread()

{

// super ("Using Thread class");

System.out.println("Child thread :"+this);

start();

}

public void run()

{

try

{

for (int i=5;i >0;i--){

System.out.println("Child thread :"+i);

Thread.sleep(500);

}

}catch (InterruptedException e){}

System.out.println("Exiting Child thread ..");

}

}

class TestMyThread

{


{

new MyThread();

try

{

for (int k=5;k >0;k--)

{

System.out.println("Running main thread :"+k);

Thread.sleep(1000);}

}catch (InterruptedException e){}

System.out.println(" Exiting Main thread..");

}

}

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// Using Thread methods

class ThreadMethod1{


Thread t=Thread.currentThread();

System.out.println("current thread:"+t);

System.out.println("Name of the current thread:"+t.getName());System.out.println("Priority:"+t.getPriority());

t.setName("mythread");

System.out.println("after name change:"+t);

t.setPriority(2);

System.out.println("after priority change:"+t);

System.out.println("number of active threads:"+t.activeCount());

}

}

// Without Synchronization

class Callme

{

void call (String msg)

{

System.out.print("[" + msg);

try

{

Thread.sleep(1000);

} catch (InterruptedException e){

System.out.println("Interrupted");

}

System.out.println("]");

}

}

class Caller implements Runnable

{

String msg;

Callme target;

Thread t;

public Caller(Callme targ, String s)

{

target = targ;

msg = s;

t = new Thread(this);

t.start();

}

public void run()

{target.call(msg);

}

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}

class Synch

{


{

Callme target = new Callme();Caller ob1 = new Caller(target, "Hello");

Caller ob2 = new Caller(target, "Synchronized");

Caller ob3 = new Caller(target, "World");

// wait for a threads to end

try

{

ob1.t.join();

ob2.t.join();

ob3.t.join();

} catch(InterruptedException e)

{System.out.println("Interrupted");

}

}

}

// With Synchronization

class Callme

{

void call (String msg)

{

System.out.print("[" + msg);

try

{

Thread.sleep(1000);

} catch (InterruptedException e){


}

System.out.println("]");

}}

class Caller implements Runnable

{

String msg;

Callme target;

Thread t;

public Caller(Callme targ, String s)

{

target = targ;msg = s;

t = new Thread(this);

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t.start();

}

public void run()

{

synchronized(target) // Synchronized block

{target.call(msg);

}

}

}

class Synch

{


{

Callme target = new Callme();

Caller ob1 = new Caller(target, "Hello");Caller ob2 = new Caller(target, "Synchronized");

Caller ob3 = new Caller(target, "World");

// wait for a threads to end

try

{

ob1.t.join();

ob2.t.join();

ob3.t.join();

} catch(InterruptedException e)

{


}

}

}

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// Java.io Package io streams

import java.io.*;

class ByteArray

{

public static void main(String args [ ] ) throws Exception{

ByteArrayOutputStream f = new ByteArrayOutputStream(10);

System.out.println("enter 10 characters and press the Enter key");

System.out.println("These will be converted to uppercase and displayed");

while (f.size( ) != 10)

{

f.write(System.in.read( ) );

}

System.out.println("Accepted characters into an array");

byte b[ ] = f.toByteArray( );

System.out.println("displaying characters in the array");for(int l=0; l


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System.out.println(c);

} while (c != 'q');

}

}

// Read a string from console using a BufferedReaderimport java.io.*;

class BRReadLines

{

public static void main(String[] args) throws IOException

{

// create a BufferedReader using System.in

String str;

BufferedReader br = new BufferedReader(new InputStreamReader (System.in));

System.out.println("Enter lines of text.");

System.out.println("Enter 'stop' to quit.");

do{

str = br.readLine();

System.out.println(str);

} while (!str.equals("stop"));

}

}

import java.io.*;

class DataStream

{

public static void main(String args[ ]) throws IOException

{

BufferedReader d=new BufferedReader(new InputStreamReader(new

FileInputStream("c:/SemIV/IOPackage/temp.txt")));

DataOutputStream o=new DataOutputStream(new

FileOutputStream("c:/SemIV/IOPackage/temp"));

String line;

while((line=d.readLine()) !=null)

{String a=(line.toUpperCase());

System.out.println(a);

o.writeBytes(a);

}

d.close();

o.close();

}

}

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// Reading and Writing to and from a file

import java.io.*;

class ReadWriteFile

{

public static byte getInput ( )[ ] throws Exception{

byte inp[ ] = new byte[50];

System.out.println("enter text.");

System.out.println("only 50 bytes i.e. about 2 lines ...");

System.out.println("press enter after each line to get input into the program");

for (int i=0;i


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// Swings and Layout Managers

// Buttons

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class Button1 extends JFrame implements ActionListener

{

JButton mtextbtn1;

JButton mtextbtn2;

JButton mtextbtn3;

JButton mtextbtn4;

JButton mtextbtn5;

public Button1()

{

setTitle("BUTTON EXAMPLE");JPanel contentpane = (JPanel)getContentPane();

contentpane.setLayout(new FlowLayout());

//contentpane.setLayout(new GridLayout(2,3));

mtextbtn1 = new JButton("Enabled");

mtextbtn1.setMnemonic('E');

mtextbtn1.addActionListener(this);

contentpane.add(mtextbtn1);

mtextbtn2 = new JButton("Disabled");

mtextbtn2.setMnemonic('D');



mtextbtn3 = new JButton("Add");

mtextbtn3.setMnemonic('A');



mtextbtn4 = new JButton("Fourth");

mtextbtn4.setMnemonic('F');mtextbtn4.addActionListener(this);


mtextbtn5 = new JButton("Fifth");

mtextbtn5.setMnemonic('T');



mtextbtn1.setEnabled(true);

myadapter myapp = new myadapter();

addWindowListener(myapp);}

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class myadapter extends WindowAdapter

{

public void windowClosing(WindowEvent e)

{

System.exit(0);}

}

public void actionPerformed(ActionEvent e)

{

if(e.getSource() == mtextbtn1)

{

setTitle("First Button Clicked");

}

else if (e.getSource() == mtextbtn2)

{setTitle("Second Button Clicked");

}


{

setTitle("Add Button Clicked");

}


{

setTitle("Fourth Button Clicked");

}


{

setTitle("Fifth Button Clicked");

}

}


{

Button1 b = new Button1();

b.setSize(100,100);

b.setVisible(true);}

}

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// Labels

import java.awt.*;



public class Labels extends JFrame

{

JLabel j1,j2,j3,j4;public Labels()

{

JPanel contentpane = (JPanel)getContentPane();

contentpane.setLayout(new GridLayout(4,1));

setTitle("Label Example");

j1 = new JLabel ("First label");

j1.setFont(new Font("Arial",Font.PLAIN,14));

contentpane.add(j1);

j2 = new JLabel("Just Text");

j2.setFont(new Font("Serif",Font.BOLD,10));contentpane.add(j2);

j3 = new JLabel("can display an imag here");

j3.setFont(new Font("TimesRoman",Font.ITALIC,12));


j4 = new JLabel("Last label to be created");

j4.setFont(new Font("SansSerif",Font.BOLD+Font.ITALIC,16));


myadapter myapp=new myadapter();

addWindowListener(myapp);

}


{


{

System.exit(0);

}

}


Labels lbl = new Labels();

lbl.setSize(250,250);

lbl.setVisible(true);

}

}

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// Text field

import java.awt.*;



import javax.swing.text.*;

public class Textf extends JFrame

{

JTextField la;

public Textf()

{

setTitle("Text Field instance");


contentpane.setLayout(new FlowLayout());

la = new JTextField(25);

la.setFont(new Font("Arial",Font.PLAIN,14));

contentpane.add(la);myadapter myapp = new myadapter();


}


{


{

System.exit(0);

}

}


{

Textf tt = new Textf();

tt.setSize(250,250);

tt.setVisible(true);

}

}

// Text area

import java.awt.*;



import javax.swing.text.*;

public class Textarea extends JFrame

{

JTextArea jtx;

public Textarea()

{JPanel contentpane = (JPanel)getContentPane();

contentpane.setLayout(new BorderLayout());

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setTitle("Text Area Example");

jtx = new JTextArea();

jtx.setFont(new Font("Arial",Font.PLAIN,14));

contentpane.add("Center",jtx);

//contentpane.add("East",jtx);

JLabel j1;j1 = new JLabel ("First label");

j1.setFont(new Font("Arial",Font.BOLD,14));

contentpane.add("North",j1);

JLabel j2= new JLabel ("status bar");

// j2.setFont(new Font("Arial",Font.BOLD,14));

contentpane.add("South",j2);



}


{


{

System.exit(0);

}

}


{

Textarea tx = new Textarea();

tx.setSize(150,150);

tx.setVisible(true);

}

}

//Check box

import java.awt.*;

import java.awt.event.*;import javax.swing.*;

public class Checkbox extends JFrame implements ItemListener

{

JCheckBox cbox;

public Checkbox()

{

setTitle("Check Box Example");


contentpane.setLayout(new GridLayout(1, 1));

cbox = new JCheckBox("Toggle");cbox.addItemListener(this);

contentpane.add(cbox);

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}


{

public void windowClosing(WindowEvent e){

System.exit(0);

}

}

public void itemStateChanged(ItemEvent e)

{

if(e.getStateChange() == ItemEvent.SELECTED)

setTitle("Checkbox selected");

else

setTitle("Checkbox unselected");}


{

Checkbox c = new Checkbox();

c.setVisible(true);

c.setSize(100,100);

}

}

// Radio buttons

import java.awt.*;



public class Checkbox extends JFrame implements ItemListener

{

JCheckBox cbox;

public Checkbox()

{setTitle("Check Box Example");


contentpane.setLayout(new GridLayout(1, 1));

cbox = new JCheckBox("Toggle");

cbox.addItemListener(this);

contentpane.add(cbox);



}

class myadapter extends WindowAdapter{


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{

System.exit(0);

}

}

public void itemStateChanged(ItemEvent e)

{if(e.getStateChange() == ItemEvent.SELECTED)

setTitle("Checkbox selected");

else

setTitle("Checkbox unselected");

}


{Checkbox c = new Checkbox();

c.setVisible(true);

c.setSize(100,100);

}

}

// Menu creation

/*

*/

import java.awt.*;



public class UseMenu extends JApplet

{

public void init()

{

Container cont = this.getContentPane();cont.setLayout(new BorderLayout());

JMenuBar mb = new JMenuBar();

cont.add(mb, BorderLayout.NORTH);

JMenu file = new JMenu("File");

file.add(new JMenuItem("New"));

file.add(new JMenuItem("Open"));

file.addSeparator();

file.add(new JMenuItem("Save") );file.add(new JMenuItem("Close") );

mb.add(file);

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JMenu edit = new JMenu("Edit");

edit.add(new JMenuItem("Undo"));

edit.add(new JMenuItem("Redo"));

edit.addSeparator();

edit.add(new JMenuItem("Cut Ctrl+X"));

edit.add(new JMenuItem("Copy Ctrl+C;"));

edit.add(new JMenuItem("Paste Ctrl+V"));

edit.add(new JMenuItem("Select All"));

// creating a sub menu

JMenu clear = new JMenu("clear");

clear.add(new JMenuItem("All"));clear.add(new JMenuItem("Format"));

clear.add(new JMenuItem("Contents"));

edit.add(clear);

mb.add(edit);

}

}

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// Applets

// A Simple Applet

/*

*/

import java.awt.*;



public class Applets1 extends JApplet

{

JButton but1;

public void init()

{


but1 = new JButton("Displayed in an Applet");

contentpane.add(but1);}

}

// A Simple Applet

/*

*/

import java.awt.*;

import java.applet.Applet;


public class SmileApplet extends Applet implements MouseMotionListener

{

public void init( ) {

addMouseMotionListener(this);

}

public void paint(Graphics g)

{

Font f = new Font ("Helvetica",Font.BOLD,20);

g.setFont(f);

g.drawString("always keep smiling !!",50,30);

g.drawOval(60,60,200,200);g.fillOval(90,120,50,20);

g.fillOval(190,120,50,20);

g.drawLine(165,125,165,175);

g.drawArc(110,130,95,95,0,-180);

g.drawLine(165,175,150,160);

}

public void mouseMoved(MouseEvent e)

{

showStatus("" + e.getX( ) + "," + e.getY( ) );

}public void mouseDragged (MouseEvent e) {}

}

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// Font Metrics

/*

*/

import java.applet.*;import java.awt.*;

public class fontMetrics extends Applet {

Font f1,f2;

int ascent, descent, height, leading;

String one,two,three,four;

public void init ( )

{

f1 = new Font("Helvetica", Font.BOLD,14);

f2 = new Font("TimesRoman", Font.BOLD+Font.ITALIC,12);}

public void paint (Graphics g) {

g.setFont (f1);

ascent = g.getFontMetrics( ).getAscent( );

descent = g.getFontMetrics( ).getDescent( );

height = g.getFontMetrics( ).getHeight( );

leading = g.getFontMetrics( ).getLeading( );

one = "Ascent of font f1 is: " + ascent;

two = "Descent of font f1 is: " + descent;

three = "Leading of font f1 is: " + leading;

four = "Height of font f1 is: " + height;

g.drawString(one, 20,20);

g.drawString(two, 20,50);

g.drawString(three,20,80);

g.drawString(four, 20,110);

}

}

// Image demo

/*

*/

import java.applet.Applet;

import java.awt.*;

public class ImageDemo extends Applet

{Image img;

public void init ( )

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{

img=getImage(getCodeBase(),"rabbit.gif");

}

public void paint (Graphics g)

{

g.drawImage(img,10,10,this);

}}

// Passing Parameters

/*

*/

import java.awt.*;public class ParamApp extends java.applet.Applet

{

Font f = new Font("TimesNewRoman",Font.BOLD, 40);

String name;

public void init()

{

name = getParameter("name");

if (name == null)

name = "friend";

name="have a nice day dear " + name;

}

public void paint(Graphics g)

{

g.setFont(f);

g.setColor(Color.darkGray);

g.drawString(name,50,50);

}

}

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