Readline() function is not reading the message sent

Question

Hi I developed a small socket server to receive GPS positions over IP. the system is very simple it listen to a port using the following syntax
Server.this.socket = Server.this.ssocket.accept();
and when a client is connected a new thread will be created using the following syntax
try {
Server.this.clientThread = new ClientThread(Server.this.socket);
Thread t = new Thread(Server.this.clientThread);
Server.this.clientThread.addObserver(Server.this);
Server.this.clients.addElement(Server.this.clientThread);
System.out.println("System reading the process 4");
t.start();
} catch (IOException ioe) {
System.out.println("Thread Error");
try{
System.out.println("Start reading the buffer ");
in = new BufferedReader(new InputStreamReader(Server.this.socket.getInputStream()));
out = new PrintWriter(Server.this.socket.getOutputStream(), true);
} catch (IOException e) {
System.out.println(e);
System.exit(-1);
line = in.readLine();
Normally when I run it in a lan environment the system is well functionning and I recieve the data properly. but when I upload it to the hosting server the software is blocked on the level of
line = in.readLine();
and stop execution after that line and if I disconnect the client software that I am using for testing the software will crash.

Answer 1

thank you for your response in fact I surely made some research while developping and had a lo of code and sample that I combined together. In my question I added small part of the code. In Fact the exceptions for readline can be througn be on level "WriteLog("Thread Error "+ioe);"
In fact this program function very good in local environment. it seems the program is crashing on the level of readline() but nothing is writen on the log file.
in our lan environment I can send messages from several stations in the same time and insert them in the database properly.
package com.usal.serverPattern;
import java.net.*;
import java.util.*;
import java.io.*;
import java.sql.*;
import java.text.*;
import java.awt.*;
public class Server implements Observer {
private Socket socket;
private Vector clients;
private ServerSocket ssocket; //Server Socket
private StartServerThread sst; //inner class
private SimpleDateFormat formatter; // Formats the date displayed
private ClientThread clientThread;
/** Port number of Server. */
private int port;
private boolean listening; //status for listening
public Server() {
this.clients = new Vector();
this.port = 2029; //default port
this.listening = false;
public void startServer() {
if (!listening) {
this.sst = new StartServerThread();
this.sst.start();
this.listening = true;
System.out.println("Server Started");
WriteLog("Server Started");
public void stopServer() {
if (this.listening) {
this.sst.stopServerThread();
//close all connected clients//
System.out.println("Threadclosed");
WriteLog("Thread closed");
java.util.Enumeration e = this.clients.elements();
while(e.hasMoreElements()) {
ClientThread ct = (ClientThread)e.nextElement();
ct.stopClient();
this.listening = false;
public void update(Observable observable, Object object) {
//notified by observables, do cleanup here//
this.clients.removeElement(observable);}
public int getPort()
return port;
public void setPort(int port)
this.port = port;
private class StartServerThread extends Thread {
private boolean listen;
public StartServerThread() {
this.listen = false;
public void run() {
String line;
BufferedReader in = null;
PrintWriter out = null;
this.listen = true;
try {
Server.this.ssocket = new ServerSocket(Server.this.port);
while (this.listen) {
//wait for client to connect//
Server.this.socket = Server.this.ssocket.accept();
System.out.println("Client connected ");
WriteLog("Client connected ");
try {
Server.this.clientThread = new ClientThread(Server.this.socket);
WriteLog("System reading the process 1");
System.out.println("System reading the process 1");
Thread t = new Thread(Server.this.clientThread);
WriteLog("System reading the process 2");
System.out.println("System reading the process 2");
Server.this.clientThread.addObserver(Server.this);
WriteLog("System reading the process 3");
System.out.println("System reading the process 3");
Server.this.clients.addElement(Server.this.clientThread);
WriteLog("System reading the process 4");
System.out.println("System reading the process 4");
t.start();
System.out.println("Server Thread Server Started ");
WriteLog("Server Thread Server Started ");
} catch (IOException ioe) {
//some error occured in ClientThread //
WriteLog("Thread Error 1"+ioe);
System.out.println("Thread Error"+ioe);
try{
WriteLog("Start reading the buffer ");
System.out.println("Start reading the buffer ");
in = new BufferedReader(new InputStreamReader(Server.this.socket.getInputStream()));
out = new PrintWriter(Server.this.socket.getOutputStream(), true);
} catch (IOException e) {
System.out.println("Accept failed: 2029"+e);
WriteLog("Accept failed: 2029");
System.exit(-1);
WriteLog("Start reading the Info ");
line = in.readLine();
WriteLog("Finish reading the info ");
java.util.Date currentDate;
currentDate = new java.util.Date();
formatter = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss", Locale.getDefault());
Statement stmt = null;
//making the database connection
try {
String dsn = "jdbc:odbc:IntegralFleet";
String user = "paty";
String password = "takingflight501";
// Connect to the database
Connection conn = DriverManager.getConnection(dsn, user, password);
stmt = conn.createStatement();
stmt.execute("Insert into socketvehi (IDVEHI, Message, Date) Values('Vehi1', '"+ line +"', '"+ formatter.format(currentDate) +"')");
System.out.println("DataBase Updated");
WriteLog("DataBase Updated");
stmt.close();
stmt = null;
catch (SQLException ex) {
// handle any errors
System.out.println("SQLException: " + ex.getMessage());
WriteLog("SQLException: " + ex.getMessage());
System.out.println("SQLState: " + ex.getSQLState());
WriteLog("SQLState: " + ex.getSQLState());
WriteLog("VendorError: " + ex.getErrorCode());
} catch (IOException ioe) {
WriteLog("Thread Error "+ioe);
public void stopServerThread() {
try {
Server.this.ssocket.close();
catch (IOException ioe) {
//unable to close ServerSocket
WriteLog("unable to close ServerSocket "+ioe);
this.listen = false;
public void ExecSQL(String strSQL){
Statement stmt = null;
//making the database connection
try {
//Connection conn = DriverManager.getConnection("jdbc:mysql://Localhost/MapServer?user=gas&password=test");
Connection conn = DriverManager.getConnection("jdbc:microsoft:sqlserver://GISLEB1:1433","sa","");
stmt = conn.createStatement();
stmt.execute(strSQL);
stmt.close();
stmt = null;
catch (SQLException ex) {
// handle any errors
System.out.println("SQLException: " + ex.getMessage());
WriteLog("SQLException: " + ex.getMessage());
System.out.println("SQLState: " + ex.getSQLState());
WriteLog("SQLState: " + ex.getSQLState());
WriteLog("VendorError: " + ex.getErrorCode());
public void ParseMessage(String strValue){
//Variables Declaration
String strTime;
String[] strSplitValue;
String strDate;
String strLatitude;
String strLongitude;
String strMinutes;
String strREQ;
float fltMinutes;
strSplitValue = strValue.split(",");
strTime = strSplitValue[1].substring(0,2)+":";
strTime = strTime+strSplitValue[1].substring(3,2)+":";
strTime = strTime+strSplitValue[1].substring(4,2);
strLatitude = strSplitValue[3].substring(0,2);
strMinutes = strSplitValue[3].substring(3,7);
fltMinutes = Float.parseFloat(strMinutes)/60;
strLatitude = strLatitude+":"+fltMinutes;
strLongitude = strSplitValue[5].substring(0,2);
strMinutes = strSplitValue[5].substring(3,7);
fltMinutes = Float.parseFloat(strMinutes)/60;
strLongitude = strLongitude+":"+fltMinutes;
strDate = strSplitValue[9].substring(0,2)+"-";
strDate = strDate+strSplitValue[9].substring(3,2)+"-";
strDate = strDate+strSplitValue[9].substring(4,2);
strREQ = "Insert into socketvehi (Time, Valid, Latitude, Longitude, Speed, Date) Values('"+strTime+"', '"+strSplitValue[2]+"', "+
strLatitude+", "+strLongitude+","+strSplitValue[7]+",'"+strDate+"')";
ExecSQL(strREQ);
public void WriteLog(String Value) {
String textline = null;
String AddText = "";
java.util.Date currentDate;
currentDate = new java.util.Date();
try {
FileReader file=new FileReader("LOG.DAT");
BufferedReader buffer=new BufferedReader(file);
while((textline = buffer.readLine()) != null)
AddText = AddText+textline+"\t\n";
buffer.close();
catch (IOException e) {System.out.println(e);
AddText = AddText+Value+" " + currentDate.toString();
try {
FileWriter file = new FileWriter("LOG.DAT");
BufferedWriter buffer1 = new BufferedWriter(file);
buffer1.write(AddText);
buffer1.close();
catch (IOException e) {System.out.println(e);
public static void main(String[] args){
//Loading the db Drivers
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
} catch (Exception ex) {
System.out.println(ex);
System.exit(-1);
Server Svr = new Server();
Svr.startServer();
}