Bug in the program!!!

Question

i have a server file as
//TCPServer.java
import java.io.*;
import java.net.*;
class TCPServer
public static void main(String argv[]) throws Exception
String clientSentence;
String capitalizedSentence;
ServerSocket welcomeSocket = new ServerSocket(6789);
while(true)
Socket connectionSocket = welcomeSocket.accept();
BufferedReader inFromClient =
new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
DataOutputStream outToClient = new DataOutputStream(connectionSocket.getOutputStream());
clientSentence = inFromClient.readLine();
System.out.println("Received: " + clientSentence);
capitalizedSentence = clientSentence.toUpperCase() + '\n';
outToClient.writeBytes(capitalizedSentence);
and a client file as
//ViewEntry.java
* @author Chinmay
import java.awt.*;
import java.awt.event.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.*;
import java.util.*;
import java.sql.*;
import java.io.*;
import java.net.*;
public class ViewEntry extends JFrame implements ActionListener,ItemListener {
JTable table;
JButton save,view;
JPanel panel;
JScrollPane jsp;
Vector col,data,row;
JMenuBar mbar;
JMenu file;
JMenuItem sav;
Connection connection;
PreparedStatement ps;
ResultSetMetaData rmeta;
ResultSet rs;
static String tableName;
Dimension screen;
JComboBox projects;
public ViewEntry(){
//super("View Data",true,true,false,true);
panel = new JPanel();
this.getContentPane().add(panel);
save = new JButton("Save");
projects = new JComboBox();
view = new JButton("View");
panel.setLayout(null);
panel.add(projects);
projects.setBounds(300,50,150,20);
panel.add(view);
panel.add(save);
save.addActionListener(this);
save.setBounds(600,100,100,25);
view.setBounds(500,50,100,25);
view.addActionListener(this);
//panel.add(save);
save.addActionListener(this);
mbar = new JMenuBar();
file = new JMenu("File");
sav = new JMenuItem("Save");
mbar.add(file);
file.add(sav);
sav.addActionListener(this);
this.setJMenuBar(mbar);
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
connection= DriverManager.getConnection("jdbc:odbc:ibc");
ps = connection.prepareStatement("Select * from Projects");
rs = ps.executeQuery();
while(rs.next()){
projects.addItem(rs.getString(2)+"_"+rs.getString(7));
catch(Exception ex){
JOptionPane.showMessageDialog(this, ex);
/*screen = StartPage.desktop.getSize();
int w = 700;
int hi = 600;
int x = (screen.width - w) / 2;
int y = (screen.height - hi) / 2;
this.setBounds(x, y, w, hi);*/
this.setVisible(true);
this.setSize(800,800);
// this.setMaximizable(true);
public static void main(String[] args){
new ViewEntry();
public void actionPerformed(ActionEvent e) {
if(e.getSource()==view){
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
connection = DriverManager.getConnection("jdbc:odbc:ibc");
tableName = (String)projects.getSelectedItem();
ps = connection.prepareStatement("Select * from "+tableName);
rs = ps.executeQuery();
rmeta = rs.getMetaData();
int colcount = rmeta.getColumnCount();
col = new Vector(colcount);
data = new Vector();
for(int i=1;i<=colcount;i++){
col.add(rmeta.getColumnName(i));
while(rs.next()){
row = new Vector(colcount);
for(int i=1;i<=colcount;i++){
row.add(rs.getString(i));
data.add(row);
table = new JTable(data, col);
int v = ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED;
int h = ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED;
jsp = new JScrollPane(table, v, h);
panel.add(jsp);
jsp.setBounds(150,80,500,400);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
} catch (Exception ex) {
JOptionPane.showMessageDialog(this, ex);
if(e.getSource()==save){
try {
transfer();
} catch (Exception ex) {
System.out.println("Error : "+ex);
public void itemStateChanged(ItemEvent e) {
if(e.getSource()==projects){
tableName = (String)projects.getSelectedItem();
JOptionPane.showMessageDialog(this, tableName);
private void transfer() throws Exception {
String sentence;
String modifiedSentence;
Socket clientSocket = new Socket("localhost", 6789);
DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
sentence = "Hi";
outToServer.writeBytes(sentence+"\n");
modifiedSentence = inFromServer.readLine();
System.out.println("FROM SERVER: " + modifiedSentence);
clientSocket.close();
i want to send a string to the server file and then the server converts the string to upper case and sends again back to client. This program is working fine but the problem when i click the save button the client sends string 2 times and sever responds 2 times. Please tell me what the exact problem is. Please help me

Answer 1

Please repost your code using the CODE button above to preserve its formatting. Nobody is going to review it in its current state. But you do need to be aware that you have added 'this' as an ActionListener at least 3 times instead of once, so getting multiple events on the same action isn't too surprising.