java programs

JAVA PROGRAMS T.Y.B.Sc(CS) 1. Write a Java program to create a class FileWatcher that can be given several filenames

that may or may not exist. The class should start a thread for each filename. Each

thread will periodically check for the existence of its file. If the file exists, then thread

will display the details of the file (viz. filename, permissions and size) on the console and

then end. If file does not exist then display appropriate error message. import java.io.*;

class FileWatcher extends Thread

{

String fileName;

FileWatcher(String fileName)

{

this.fileName = fileName;

}

public void run()

{

File f = new File(fileName);

while(true)

{

try

{

if(f.exists())

{

System.out.println("File "+fileName+

" found.");

System.out.println("Name:"+f.getName()+

"\nRead:"+f.canRead()+

"\nWrite:"+f.canWrite()+

"\nsize:"+f.length());

break;

}

else

{

System.out.println("File "+fileName+

" not found.");

}

Thread.sleep(200);

}

catch(Exception e){}

}

}

}

class FileWatcherDemo

{

public static void main(String args[])

{

int n = args.length;

for(int i=0;i

System.out.println("From Server:"+br.readLine());

}

}

3. Write a menu driven JDBC program to display the first record, last record, middle

record, nth record of a student,(Student table should contain student id, name and class)

(Note: Examiners can replace Student table with Item, Book, Supplier, Customer,

Doctor, Patient or any other and provide the design of the table) import java.io.*;

import java.sql.*;

class StudentDB

{

static BufferedReader br = new BufferedReader(

new InputStreamReader(System.in));

static void dispRecord(ResultSet rs) throws Exception

{

System.out.println("ID:"+rs.getInt(1)+

"\nName:"+rs.getString(2)+

"\nClass:"+rs.getString(3));

}


{

String driver="com.mysql.jdbc.Driver";

String url="jdbc:mysql://localhost:3306/tybcs1";

String user="root";

String pass="";

String sql="SELECT * FROM student";

Connection con = null;

Statement s = null;

ResultSet rs = null;

try

{

Class.forName(driver);

con = DriverManager.getConnection(url,user,pass);

s = con.createStatement(

ResultSet.TYPE_SCROLL_SENSITIVE,

ResultSet.CONCUR_READ_ONLY);

rs = s.executeQuery(sql);

while(true)

{

System.out.print("1.First record"+

"\n2.Last record"+

"\n3.Middle record"+

"\n4.nth record"+

"\n5.Exit"+

"\nEnter ur choice (1-5):");

int ch=Integer.parseInt(br.readLine());

switch(ch)

{

case 1:

rs.first();

dispRecord(rs);

break;

case 2:

rs.last();

dispRecord(rs);

break;

case 3:

rs.last();

int mid=rs.getRow();

rs.absolute(mid/2);

dispRecord(rs);

break;

case 4:

System.out.print("Enter record no:");

int n = Integer.parseInt(br.readLine());

rs.last();

if(n>0 && n

class MyThread extends Thread

{

JTextField tf;

MyThread(JTextField tf)

{

this.tf = tf;

}

public void run()

{

while(true)

{

Date d = new Date();

int h = d.getHours();

int m = d.getMinutes();

int s = d.getSeconds();

tf.setText(h+":"+m+":"+s);

try

{

Thread.sleep(300);

}catch(Exception e){}

}

}

}

class StopWatch extends JFrame

{

JTextField txtTime;

JButton btnStart,btnStop;

MyThread t;

StopWatch()

{

txtTime = new JTextField(20);

btnStart = new JButton("Start");

btnStop = new JButton("Stop");

setTitle("Stop Watch");

setLayout(new FlowLayout());

setSize(300,100);

add(txtTime);

add(btnStart);

add(btnStop);

setVisible(true);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

ButtonHandler bh = new ButtonHandler();

btnStart.addActionListener(bh);

btnStop.addActionListener(bh);

t = new MyThread(txtTime);

}

class ButtonHandler implements ActionListener

{

public void actionPerformed(ActionEvent ae)

{

if(ae.getSource()==btnStart)

{

if(!t.isAlive()) t.start();

else t.resume();

}

if(ae.getSource()==btnStop)

{

t.suspend();

}

}

}


{

new StopWatch();

}

}

5. Write a servlet which counts how many times a user has visited a web page. If the user

is visiting the page for the first time, display a welcome message. If the user is revisiting

the page, display the number of times visited. (Use cookies) import java.io.*;

import javax.servlet.*;

import javax.servlet.http.*;

public class HitCount extends HttpServlet

{

public void doGet(HttpServletRequest request,

HttpServletResponse response)

throws ServletException,IOException

{

response.setContentType("text/html");

PrintWriter out = response.getWriter();

Cookie c[]=request.getCookies();

if(c==null)

{

Cookie cookie = new Cookie("count","1");

response.addCookie(cookie);

out.println("Welcome Servlet"+

"Hit Count:1");

}

else

{

int val=Integer.parseInt(c[0].getValue())+1;

c[0].setValue(Integer.toString(val));

response.addCookie(c[0]);

out.println("Hit Count:"+val+"");

}

}

}

6. Create a JSP page to accept a number from the user and display it in words.

eg. 125 One Two Five

The output should be in blue color.

// number.html

Enter Number:

// words.jsp

// user.jsp


int ch=0;

try

{



ps = con.prepareStatement(insertSQL);

do

{

System.out.print("Enter roll no:");

int rno=Integer.parseInt(br.readLine());

System.out.print("Enter name:");

String name=br.readLine();

System.out.print("Enter marks 1:");

float m1=Float.parseFloat(br.readLine());





ps.setInt(1,rno);

ps.setString(2,name);

ps.setFloat(3,m1);

ps.setFloat(4,m2);

ps.setFloat(5,m3);

ps.executeUpdate();

System.out.print("Add More[Yes(1)/No(0)]?");

ch=Integer.parseInt(br.readLine());

}while(ch==1);

ps.close();

ps=con.prepareStatement(sql);

rs=ps.executeQuery();

System.out.println("RollNo\tName\tMarks1\tMarks2\t"+

"Marks3\tTotal\tPercentage");

while(rs.next())

{

float m1=rs.getFloat(3);



float tot=m1+m2+m3;

float per=tot/3;

System.out.println(rs.getInt(1)+"\t"+

rs.getString(2)+"\t"+

rs.getFloat(3)+"\t"+



tot+"\t"+per);

}

rs.close();

ps.close();

con.close();

}

catch(Exception e)

{

System.out.println(e);

}

}

}

9. Create two singly linked lists for string data and perform following operations

a) Add element in list1 b) Add element in list2 c) Union

d) Display the reverse of the linked list after the union of lists e) Intersection

f) exit import java.util.*; import java.io.*;

class LinkedListDemo

{


throws Exception

{

LinkedList ll1 = new LinkedList();




BufferedReader br = new BufferedReader(

new InputStreamReader(

System.in));

String s=null;

while(true)

{

System.out.println("1.Add element in list 1"+

"\n2.Add element in list 2"+

"\n3.Union"+

"\n4.Display reverse of union"+

"\n5.Intersection"+

"\n6.Exit"+



switch(ch)

{

case 1:

System.out.print("Enter element:");

s = br.readLine();

if(!ll1.contains(s)) ll1.add(s);

break;

case 2:

System.out.print("Enter element:");

s = br.readLine();

if(!ll2.contains(s)) ll2.add(s);

break;

case 3:

ll3.addAll(ll1);

for(String t:ll2)

{

if(!ll3.contains(t)) ll3.add(t);

}

System.out.println("List 1:"+ll1+

"\nList 2:"+ll2+

"\nList 3:"+ll3);

break;

case 4:

int n = ll3.size();

ListIterator iter =

ll3.listIterator(n);

System.out.println("Elements in reverse:");

int i=1;

while(iter.hasPrevious())

{

String e = iter.previous();

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

}

break;

case 5:

for(String t:ll1)

{

if(ll2.contains(t)) ll4.add(t);

}

System.out.println("List 1:"+ll1+

"\nList 2:"+ll2+

"\nList 3:"+ll4);

break;

case 6:

System.exit(0);

}

}

}

}

10. Create a linked list containing the names of the days in a week. Display the menu that

has following options.

a) Display the contents of the list using Iterator. b) Display the contents of the list in reverse order using ListIterator

c) Accept a day and display its index in the collection d) Exit

import java.util.*;

import java.io.*;

class WeekDaysList

{


throws Exception

{

LinkedList days = new LinkedList();

days.add("Sunday");

days.add("Monday");

days.add("Tuesday");

days.add("Wednesday");

days.add("Thursday");

days.add("Firday");

days.add("Saturday");



System.in));

while(true)

{

System.out.print("1.Display list"+

"\n2.Display list in reverse"+

"\n3.Display index of day"+

"\n4.Exit"+



switch(ch)

{

case 1:

Iterator itr = days.iterator();

while(itr.hasNext())

{

System.out.println(itr.next());

}

break;

case 2:

int n = days.size();

ListIterator ritr = days.listIterator(n);

while(ritr.hasPrevious())

{

System.out.println(ritr.previous());

}

break;

case 3:

System.out.print("Enter day:");

String day = br.readLine();

int i = days.indexOf(day);

if(i==-1)

System.out.println("Invalid day");

else

System.out.println(day+" found at "+i);

break;

case 4:

System.exit(0);

}

}

}

}

11. Design a HTML page containing 4 option buttons(MBA,MSC,MCA,MCM) and two

buttons Reset and Submit. When the user clicks Submit the server responds by adding

a cookie containing the selected course and sends a message back to the client. // course.html

Select Course

MBA

MSc

MCA

MCM

View Cookies

// AddCookie.java

import java.io.*;



public class AddCookie extends HttpServlet

{

public void doPost(HttpServletRequest req,

HttpServletResponse res)


{

res.setContentType("text/html");

PrintWriter pw = res.getWriter();

Cookie []c = req.getCookies();

int id=1;

if(c!=null) id = c.length+1;

String value = req.getParameter("course");

Cookie newCookie = new Cookie("course:"+id,value);

res.addCookie(newCookie);

pw.println("Cookie added with value "+value+"");

}

}

// ViewCookies.java

import java.io.*;



public class ViewCookies extends HttpServlet

{

public void doGet(HttpServletRequest req,

HttpServletResponse res)


{

res.setContentType("text/html");

PrintWriter pw = res.getWriter();

Cookie []c = req.getCookies();

pw.println(""+

"NameValue");

for(int i=0;i

{

if(x

}

public void run()

{

while(true)

{

ta.append(count+"\n");

try

{

Thread.sleep(100);


count+=2;

if(count>100)count=0;

}

}

}

class OddThread extends Thread

{

JTextArea ta;

int count;

OddThread(JTextArea ta)

{

this.ta=ta;

count=1;

}

public void run()

{

while(true)

{

ta.append(count+"\n");

try

{

Thread.sleep(100);


count+=2;

if(count>100)count=1;

}

}

}

class EvenOdd extends JFrame

{

JTextArea taEven,taOdd;

JButton btnOdd,btnEven,btnEvenStop,btnOddStop;

JPanel panCenter,panSouth;

EvenThread et;

OddThread ot;

EvenOdd()

{

taEven = new JTextArea();

taOdd = new JTextArea();

btnOdd = new JButton("Odd");

btnEven = new JButton("Even");

btnOddStop = new JButton("Stop");

btnEvenStop = new JButton("Stop");

panCenter = new JPanel();

panCenter.setLayout(new GridLayout(1,2));

panCenter.add(new JScrollPane(taEven));

panCenter.add(new JScrollPane(taOdd));

panSouth = new JPanel();

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

panSouth.add(btnEven);

panSouth.add(btnEvenStop);

panSouth.add(btnOdd);

panSouth.add(btnOddStop);

setTitle("Even & Odd");

setSize(300,200);

add(panCenter,"Center");

add(panSouth,"South");

setVisible(true);


ButtonHandler bh = new ButtonHandler();

btnOdd.addActionListener(bh);

btnEven.addActionListener(bh);

btnOddStop.addActionListener(bh);

btnEvenStop.addActionListener(bh);

et = new EvenThread(taEven);

ot = new OddThread(taOdd);

}

class ButtonHandler implements ActionListener

{


{

if(ae.getSource()==btnEven)

{

if(et.isAlive()) et.resume();

else et.start();

}

if(ae.getSource()==btnOdd)

{

if(ot.isAlive()) ot.resume();

else ot.start();

}

if(ae.getSource()==btnEvenStop) et.suspend();

if(ae.getSource()==btnOddStop) ot.suspend();

}

}


{

new EvenOdd();

}

}

14. Write a Java program to create a Hash table to store book id and book name. Book id and name should be accepted from the console. Write a menu driven program to add,

search, delete and display the contents of the hash table. Display the contents of the

hash table in tabular format. Display all the options till Exit is selected. (Do not use

Swing). import java.io.*;

import java.util.*;

class BookHash

{


throws Exception

{



System.in));

Hashtable ht=new Hashtable();

int bid=0;

String bname=null;

while(true)

{

System.out.print("1.Add"+

"\n2.Search"+

"\n3.Delete"+

"\n4.Display"+

"\n5.Exit"+



switch(ch)

{

case 1:

System.out.print("Enter book id:");

bid = Integer.parseInt(br.readLine());

System.out.print("Enter book name:");

bname = br.readLine();

ht.put(bid,bname);

break;

case 2:



bname = ht.get(bid);

if(bname==null)

System.out.println("Book not found.");

else

System.out.println("Book Name:"+bname);

break;

case 3:



bname = ht.remove(bid);

if(bname==null)

System.out.println("Book not found.");

else

System.out.println("Book removed.");

break;

case 4:

Enumeration e = ht.keys();

System.out.println("ID\tName");

while(e.hasMoreElements())

{

bid = (Integer)e.nextElement();

bname = ht.get(bid);

System.out.println(bid+"\t"+bname);

}

break;

case 5:

System.exit(0);

}

}

}

}

15. Write a Java program to accept n student names from console and display the sorted list in descending order (Use Comparator).

(Note: The examiners can change the data that is to be stored in the List i.e. instead of

student names, accept n book names or item names or city names etc.) import java.util.*;

import java.io.*;

class Student

{

private int rollNo;

private String name;

private float per;

Student(int rollNo, String name, float per)

{

this.rollNo=rollNo;

this.name=name;

this.per=per;

}

public String toString()

{

return rollNo+"\t"+name+"\t"+per;

}

public String getName()

{

return name;

}

}

class NameComparator implements Comparator

{

public int compare(Object ob1, Object ob2)

{

String n1 = ((Student)ob1).getName();

String n2 = ((Student)ob2).getName();

return n1.compareTo(n2);

}

}

public class StudentSort

{


throws Exception

{



System.in));

System.out.print("Enter no.of students:");

int n = Integer.parseInt(br.readLine());

LinkedList studList = new LinkedList();

for(int i=0;i

System.out.println("Sorted Names:");

for(Student s:studList)

System.out.println(s);

}

}

16. Write a JDBC Program to accept a table name from console and display the following

details. Number of columns in the table, column names, data type and the number of

records. import java.io.*;

import java.sql.*;

class TableInfo

{

static BufferedReader br = new BufferedReader(



{

String driver="com.mysql.jdbc.Driver";

String url="jdbc:mysql://localhost:3306/tybcs1";

String user="root";

String pass="";

Connection con = null;

Statement s = null;


ResultSetMetaData rsmd = null;

try

{



System.out.print("Enter table name:");

String tname = br.readLine();

String sql = "SELECT * FROM "+tname;

s = con.createStatement(

ResultSet.TYPE_SCROLL_SENSITIVE,

ResultSet.CONCUR_READ_ONLY);

rs = s.executeQuery(sql);

rsmd = rs.getMetaData();

int noCols = rsmd.getColumnCount();

System.out.println("No.of columns:"+noCols);

for(int i=1;i

s.close();

con.close();

}

catch(Exception e)

{

System.out.println(e);

}

}

}

17. Write a Java program which sends the name of a text file from the client to server and display the contents of that file on the client machine. If the file does not exists then

display proper error message to client. // Server.java

import java.io.*;

import java.net.*;

public class Server

{


throws Exception

{

ServerSocket ss = new ServerSocket(4444);

BufferedReader fromClient = null;

PrintStream toClient = null;

BufferedReader brFile = null;

File file = null;

while(true)

{

Socket s = ss.accept();

fromClient = new BufferedReader(


s.getInputStream()));

toClient = new PrintStream(

s.getOutputStream());

String fileName = fromClient.readLine();

file = new File(fileName);

if(file.exists())

{

brFile = new BufferedReader(

new FileReader(fileName));

String line = null;

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

toClient.println(line);

}

else

{

toClient.println("File "+fileName+" Not Found.");

}

toClient.println("----");

s.close();

}

}

}

// Client.java

import java.io.*;

import java.net.*;

public class Client

{


throws Exception

{

Socket s = new Socket("localhost",4444);

BufferedReader fromServer = new BufferedReader(


s.getInputStream()));

PrintStream toServer = new PrintStream(

s.getOutputStream());



System.in));

System.out.print("Enter file name:");

String fileName = br.readLine();

toServer.println(fileName);

String line = null;

while(true)

{

line = fromServer.readLine();

if(line.equals("----")) break;

System.out.println(line);

}

s.close();

}

}

18. Write a server program that echoes messages sent by the client. The process continues

till the client types END. // Client.java

import java.io.*;

import java.net.*;

class Client

{

public static void main(String argv[]) throws Exception

{

String sentence;

String modifiedSentence;

BufferedReader inFromUser = new BufferedReader(


System.in));

Socket clientSocket = new Socket("localhost", 9005);

DataOutputStream outToServer = new DataOutputStream(

clientSocket.getOutputStream());

BufferedReader inFromServer = new BufferedReader(


clientSocket.getInputStream()));

System.out.println("Enter text (END to stop)");

while(true)

{

sentence = inFromUser.readLine();

if(sentence.equals("END")) break;

outToServer.writeBytes(sentence + '\n');

modifiedSentence = inFromServer.readLine();

System.out.println(modifiedSentence);

}

clientSocket.close();

}

}

// Server.java

import java.io.*;

import java.net.*;

class Server

{

public static void main(String argv[]) throws Exception

{

String clientSentence;

String capitalizedSentence;

ServerSocket welcomeSocket = new ServerSocket(9005);

while(true)

{

Socket connectionSocket = welcomeSocket.accept();

BufferedReader inFromClient = new BufferedReader(


connectionSocket.getInputStream()));

DataOutputStream outToClient = new DataOutputStream(

connectionSocket.getOutputStream());

clientSentence = inFromClient.readLine();

capitalizedSentence=clientSentence.toUpperCase()+'\n';

outToClient.writeBytes(capitalizedSentence);

}

}

}

19. Create a class student with attributes rno, name , age and class. Initialize values through parameterize constructor. If age of student is not in between 15 to 21 then

generate user defined exception as InvalidAgeException. Similarly if name contains special symbols or digits then raise exception as InvalidNameException. Handle these

exceptions. class InvalidAgeException extends Exception{}

class InvalidNameException extends Exception{}

class Student

{

int RollNo, Age;

String Name,Course;

Student(int rno, String name, int age, String course)

{

try

{

RollNo = rno;

Name = name;

Age = age;

Course = course;

if(Age21)

throw new InvalidAgeException();

for(int i=0; i

throw new InvalidNameException();

}

catch(InvalidAgeException e)

{

System.out.println("Age Not Within The Range");

}

catch(InvalidNameException e)

{

System.out.println("Name not valid");

}

}

public String toString()

{

return "Roll No:"+RollNo+

"\nName :"+Name+

"\nAge :"+Age+

"\nCourse :"+Course;

}

}

class StudentExceptionDemo

{


{

Student s1 = new Student(1,"Ram",17,"Java Programming");

System.out.println(s1);

Student s2 = new Student(2,"John",28,"C++ Programming");


Student s3 = new Student(3,"Akbar15",19,"C++ Programming");


}

}

20. Write a program to accept a string as command line argument and check whether it is a

file or directory. If it is a directory then list the file names and their size in that

directory. Also display a count of the number of files in the directory. Delete all the files

in that directory having the extension .txt ( Confirm from user to delete a file or not). If

it is a file then display various details about that file.

(Note: Examiners can change the file extension from .txt to .dat or .tmp or .swp etc.) import java.io.*;

class FileDemo

{


throws Exception

{



String name=args[0];

File file = new File(name);

if(file.isFile())

{

System.out.println(name+" is a file.");

}

if(file.isDirectory())

{

System.out.println(name+" is a directory.");

String names[]=file.list();

int count=0;

for(int i=0;i

System.out.print("Enter name:");

String name=br.readLine();

System.out.print("Enter class:");

String cls=br.readLine();

System.out.print("Enter percentage:");

float per=Float.parseFloat(br.readLine());

dos.writeInt(rno);

dos.writeUTF(name);

dos.writeUTF(cls);

dos.writeFloat(per);

}

dos.close();

System.out.print("Enter roll no:");

int no=Integer.parseInt(br.readLine());

DataInputStream dis = new DataInputStream(

new FileInputStream("stud.dat"));

while(true)

{

int rno=dis.readInt();

String name=dis.readUTF();

String cls=dis.readUTF();

float per=dis.readFloat();

if(rno==no)

{

System.out.println("Roll No:"+rno+

"\nName:"+name+

"\nClass:"+cls+

"\nPercentage:"+per);

break;

}

}

dis.close();

}

catch(Exception e)

{

System.out.println("Roll No Not Found.");

}

}

}

22. Write a Java program to create GUI that displays all the font names available on a

system in a ComboBox. Also display some text message. Apply the font selected from

the combo box to the text message. import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

class FontDemo extends JFrame

{

JLabel lblFont;

JComboBox cmbFont;

JTextField txtMsg;

FontDemo()

{

String fontName[] = GraphicsEnvironment.

getLocalGraphicsEnvironment().

getAvailableFontFamilyNames();

lblFont = new JLabel("Font:");

txtMsg = new JTextField("Hello World!",40);

cmbFont = new JComboBox(fontName);

setTitle("Font Demo");

setSize(400,100);

setLayout(new FlowLayout());

add(lblFont);

add(cmbFont);

add(txtMsg);

setVisible(true);


cmbFont.addItemListener(new ItemListener()

{

public void itemStateChanged(ItemEvent ie)

{

String fontName=

(String)cmbFont.getSelectedItem();

txtMsg.setFont(

new Font(fontName,Font.BOLD,15));

}

});

}


{

new FontDemo();

}

}

23. Write a Java program to design a screen using swings that will create four text fields.

First text field for the text, second for what to find and third for replace. Display result

in the fourth text field. Also display the count of total no. of replacements made. On the

click of clear button, clear the contents in all the text boxes.

import java.awt.*;



public class FindReplace extends JFrame implements ActionListener

{

JLabel textLabel, findLabel, replaceLabel, occurrenceLabel;

JTextArea text;

JTextField findText, replaceText, occurrenceText;

JButton find, replace, clear;

JPanel pan1,pan2;

int occurrences=0;

public FindReplace()

{

textLabel = new JLabel("Enter Text:",JLabel.RIGHT);

findLabel = new JLabel("Text to Find:",JLabel.RIGHT);

replaceLabel = new JLabel("Text to Replace:",

JLabel.RIGHT);

occurrenceLabel = new JLabel("No.of Occurrences:",

JLabel.RIGHT);

text = new JTextArea(1,20);

findText = new JTextField(20);

replaceText = new JTextField(20);

occurrenceText = new JTextField(20);

pan1 = new JPanel();

pan1.setLayout(new GridLayout(4,2));

pan1.add(textLabel);

pan1.add(text);

pan1.add(findLabel);

pan1.add(findText);

pan1.add(replaceLabel);

pan1.add(replaceText);

pan1.add(occurrenceLabel);

pan1.add(occurrenceText);

find = new JButton("Find");

replace = new JButton("Replace");

clear = new JButton("Clear");

find.addActionListener(this);

replace.addActionListener(this);

clear.addActionListener(this);

pan2 = new JPanel();

pan2.setLayout(new FlowLayout());

pan2.add(find);

pan2.add(replace);

pan2.add(clear);

setTitle("Find And Replace");

setSize(300, 200);

add(pan1,"Center");

add(pan2,"South");


setVisible(true);

}

public static void main(String[] args)

{

new FindReplace();

}


{

JButton btn = (JButton)ae.getSource();

if(btn == find)

{

String s = text.getText();

String f = findText.getText();

int i = s.indexOf(f);

if(i!=-1)

{

occurrences++;

occurrenceText.setText(

Integer.toString(occurrences));

text.select(i,i+f.length());

text.requestFocus();

}

}

if(btn == replace)

{

if(text.getSelectedText().length()!=0)

{

String r = replaceText.getText();

text.replaceSelection(r);

}

}

if(btn == clear)

{

text.setText("");

findText.setText("");

replaceText.setText("");

occurrenceText.setText("");

findText.requestFocus();

}

}

}

24. Create an abstract class shape. Derive three classes sphere, cone and cylinder from

shape. Calculate area and volume of all (use method overriding). import java.io.*;

abstract class Shape

{

double r,h;

Shape(double r, double h)

{

this.r = r;

this.h = h;

}

abstract double calcArea();

abstract double calcVolume();

}

class Sphere extends Shape

{

Sphere(double r)

{

super(r,0);

}

double calcArea()

{

return 4*Math.PI*r*r;

}

double calcVolume()

{

return 4*Math.PI*Math.pow(r,3)/3;

}

}

class Cone extends Shape

{

Cone(double r, double h)

{

super(r,h);

}

double calcArea()

{

return Math.PI*r*(r+Math.sqrt(r*r+h*h));

}

double calcVolume()

{

return Math.PI*r*r*h/3;

}

}

class Cylinder extends Shape

{

Cylinder(double r, double h)

{

super(r,h);

}

double calcArea()

{

return 2*Math.PI*r*(h+r);

}

double calcVolume()

{

return Math.PI*r*r*h;

}

}

class ShapeTest

{


throws Exception

{



Shape s=null;

double r=0,h=0;

while(true)

{

System.out.print("1.Sphere"+

"\n2.Cone"+

"\n3.Cylinder"+

"\n4.Exit"+

"\nEnter your choice (1-4):");

int ch = Integer.parseInt(br.readLine());

switch(ch)

{

case 1:

System.out.print("Enter radius of sphere:");

r = Double.parseDouble(br.readLine());

s = new Sphere(r);

break;

case 2:

System.out.print("Enter radius of cone:");


System.out.print("Enter height of cone:");

h = Double.parseDouble(br.readLine());

s = new Cone(r,h);

break;

case 3:

System.out.print("Enter radius of cylinder:");


System.out.print("Enter height of cylinder:");

h = Double.parseDouble(br.readLine());

s = new Cylinder(r,h);

break;

case 4:

System.exit(0);

}

System.out.println("Area = "+s.calcArea()+

"\nVolume = "+s.calcVolume());

}

}

}

25. Write a Java program to create GUI screen that display the following graphics.

Fill outer and inner rectangle with red color. Fill outer circle with yellow color and inner

circle with blue color. Draw graphical shapes in black color.

(Note: The examiners can change the graphics that is to be drawn. However, atleast 4

graphical objects need to be drawn and filled with different colors)

import java.awt.*;

import java.awt.geom.*;


class MyPanel extends JPanel

{

public void paintComponent(Graphics g)

{

Graphics2D g2d = (Graphics2D)g;

int w = getWidth();

int h = getHeight();

g2d.setPaint(Color.RED);

g2d.fill(new Rectangle2D.Float(5,5,w-10,h-10));

g2d.setPaint(Color.BLACK);

g2d.draw(new Rectangle2D.Float(5,5,w-10,h-10));

g2d.setPaint(Color.YELLOW);

g2d.fill(new Ellipse2D.Float(w/2-150,h/2-150,300,300));


g2d.draw(new Ellipse2D.Float(w/2-150,h/2-150,300,300));

g2d.setPaint(Color.BLUE);

g2d.fill(new Ellipse2D.Float(w/2-100,h/2-100,200,200));


g2d.draw(new Ellipse2D.Float(w/2-100,h/2-100,200,200));

g2d.setPaint(Color.RED);

g2d.fill(new Rectangle2D.Float(w/2-50,h/2-25,100,50));


g2d.draw(new Rectangle2D.Float(w/2-50,h/2-25,100,50));

}

}

class TwoD extends JFrame

{

TwoD()

{

setTitle("Circles & Rectangles");

setSize(400,400);

add(new MyPanel());

setVisible(true);


}


{

new TwoD();

}

}

26. Write a Java program to create the following GUI screen.

The first Scroll bar will handle red color; the second will handle green color and third will

handle the blue color. Set min = 0, max = 255 for the scroll bars. The screen has two labels

and one command button Apply. When user clicks on the Apply button, set the background color of the label1 according to the RGB values set using the scrollbars.

Display the values of Red, Green, Blue in label2. import java.awt.*;



class ScrollDemo extends JFrame

{

JScrollBar sbRed,sbBlue,sbGreen;

JLabel lblRed,lblBlue,lblGreen,lblValues;

JPanel panColor,panCenter;

JButton btnApply;

ScrollDemo()

{

sbRed = new JScrollBar(JScrollBar.HORIZONTAL,0,5,0,260);

sbGreen = new JScrollBar(JScrollBar.HORIZONTAL,0,5,0,260);

sbBlue = new JScrollBar(JScrollBar.HORIZONTAL,0,5,0,260);

lblRed = new JLabel("Red:");

lblGreen = new JLabel("Green:");

lblBlue = new JLabel("Blue:");

lblValues = new JLabel("(0,0,0)");

panColor = new JPanel();

panCenter = new JPanel();

btnApply = new JButton("Apply");

panCenter.setLayout(new GridLayout(4,2));

panCenter.add(lblRed);

panCenter.add(sbRed);

panCenter.add(lblGreen);

panCenter.add(sbGreen);

panCenter.add(lblBlue);

panCenter.add(sbBlue);

panCenter.add(lblValues);

panCenter.add(panColor);

setTitle("ScrollBar Demo");

setSize(400,200);

add(panCenter,"Center");

add(btnApply,"South");

setVisible(true);


btnApply.addActionListener(new ActionListener()

{


{

int r = sbRed.getValue();

int g = sbGreen.getValue();

int b = sbBlue.getValue();

lblValues.setText("("+r+","+g+","+b+")");

panColor.setBackground(new Color(r,g,b));

}

});

}


{

new ScrollDemo();

}

}

27. Write a Java program to create GUI screen that display the following graphics

import java.awt.*;

import java.awt.geom.*;


class MyPanel extends JPanel

{

public void paintComponent(Graphics g)

{

super.paintComponent(g);

Graphics2D g2d = (Graphics2D)g;

int w = getWidth();

int h = getHeight();

GeneralPath path = new GeneralPath();

path.moveTo(5,h/3);

path.lineTo(w/3,5);

path.lineTo(w-5,5);

path.lineTo(w-5,2*h/3);

path.lineTo(5,2*h/3);

path.closePath();

g2d.draw(path);

g2d.draw(new Rectangle2D.Float(w/3+5,10,w/6,h/4-10));

g2d.draw(new Rectangle2D.Float(w/3+w/6+35,10,w/3,h/4-10));

g2d.setPaint(Color.LIGHT_GRAY);

g2d.fill(new Ellipse2D.Float(w/4,2*h/3-50,100,100));


g2d.draw(new Ellipse2D.Float(w/4,2*h/3-50,100,100));

g2d.setPaint(Color.WHITE);

g2d.fill(new Ellipse2D.Float(w/4+30,2*h/3-25,45,45));


g2d.draw(new Ellipse2D.Float(w/4+30,2*h/3-25,45,45));

g2d.setPaint(Color.LIGHT_GRAY);




g2d.setPaint(Color.WHITE);




}

}

class CarDemo extends JFrame

{

CarDemo()

{

setTitle("Car Demo");

setSize(400,300);

add(new MyPanel());

setVisible(true);


}


{

new CarDemo();

}

}

28. Create a JSP page which accepts username and password. User can have 3 login chances only. If username and password is correct display a Welcome message else

display an error message. // Login.html

User Name:

Password:

// Login.jsp

=3)

{

out.print("Three attempts over.");

}

session.setAttribute("count",new Integer(count));

out.print("Login failed.");

}

%>

29. Write a program to create a package named Maths. Define classes as MathOp with

static methods to find the maximum and minimum of three numbers. Create another

package Stats. Define a class StatsOp with methods to find the average and median of

three numbers. Use these methods in main to perform operations on three integers

accepted using command line arguments. package Maths;

public class MathsOperations

{

public static int getMin(int a, int b, int c)

{

return a

{

return a>b?(a>c?a:c):(b>c?b:c);

}

}

package Stats;

public class StatsOperations

{

public static float avg(int a, int b, int c)

{

return (a+b+c)/3.0f;

}

public static float median(int a, int b, int c)

{

int min = ac?b:c);

return (min+max)/2.0f;

}

}

import Stats.*;

import Maths.*;

class PackTest

{


{

int x = Integer.parseInt(args[0]);

int y = Integer.parseInt(args[1]);

int z = Integer.parseInt(args[2]);

System.out.println(MathsOperations.getMin(x,y,z));

System.out.println(MathsOperations.getMax(x,y,z));

System.out.println(StatsOperations.avg(x,y,z));

System.out.println(StatsOperations.median(x,y,z));

}

}

30. Write a Java program to accept a decimal number in the text filed.. When the user

clicks the Calculate button the program should display the binary, octal, hexadecimal

equivalents.

import java.awt.*;



class Conversion extends JFrame

{

JLabel lblDec,lblBin,lblOct,lblHex;

JTextField txtDec,txtBin,txtOct,txtHex;

JButton btnCalc,btnClear;

Conversion()

{

lblDec = new JLabel("Decimal Number:");

lblBin = new JLabel("Binary Number:");

lblOct = new JLabel("Octal Number:");

lblHex = new JLabel("Hexadecimal Number:");

txtDec = new JTextField();

txtBin = new JTextField();

txtOct = new JTextField();

txtHex = new JTextField();

btnCalc = new JButton("Calculate");

btnClear = new JButton("Clear");

setTitle("Conversion");

setSize(300,250);

setLayout(new GridLayout(5,2));

add(lblDec);

add(txtDec);

add(lblBin);

add(txtBin);

add(lblOct);

add(txtOct);

add(lblHex);

add(txtHex);

add(btnCalc);

add(btnClear);

setVisible(true);


btnCalc.addActionListener(new ActionListener()

{


{

int n = Integer.parseInt(

txtDec.getText());

txtBin.setText(

Integer.toBinaryString(n));

txtOct.setText(

Integer.toOctalString(n));

txtHex.setText(

Integer.toHexString(n));

}

});

btnClear.addActionListener(new ActionListener()

{


{

txtDec.setText("");

txtBin.setText("");

txtOct.setText("");

txtHex.setText("");

txtDec.requestFocus();

}

});

}


{

new Conversion();

}

}

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