Server/Client Socket Connection

[Accela Moon]

Hi, I am trying to program a simple server/client socket connection program, the main function is to send and receive objects between them. I somehow went wrong and the connection between them keeps terminating right after establishing connection. Is there anything I can do to resolve this?
This is gonnna be kinda long post.. sorry. These are the code that starts and ends the socket connection. I'm kinda desperate for this to work.. so thanks in advance.
appinterface.java:

//Set up server to receive communications; process connections. 1x.
public void runServer () {
try {
//Create a ServerSocket
server = new ServerSocket(12345, 100);
try {
waitForSockConnection();//Wait for a connection.
getSockStreams();//Get input & output streams.
establishDbConnection();//Open up connection to DB.
}
finally {
closeSockConnection(); //Close connection.
}
}

//Process problems with I/O
catch(IOException ioException) {
displayMessage("I/O Error: " + ioException);
runServer();
}
}

//Wait for connection to arrive, then display connection info
private void waitForSockConnection() throws IOException {
displayMessage("Waiting for connection");
connection = server.accept(); //Allow server to accept connection.
displayMessage("Connection received from: " + connection.getInetAddress().getHostName());
}

//Get streams to send and receive data.
private void getSockStreams() throws IOException {

//Set up output streams for objects
ObjectOutputStream output = new ObjectOutputStream(connection.getOutputStream());
output.flush(); //Flush output buffer to send header information.

//Set up input stream for objects.
ObjectInputStream input = new ObjectInputStream(connection.getInputStream());
try {
classHolderServer holderObj = new classHolderServer();
holderObj = (classHolderServer)input.readObject();
processSockConnection(holderObj);
displayMessage("Got I/O Streams");
}
//Catch problems reading from client
catch (ClassNotFoundException classNotFoundException) {
displayMessage("Unknown object type received");
}
}

//Process connection with client.
private void processSockConnection(classHolderServer holderObj) throws IOException {
//sendMessage("Connection Successful");
//True is query, and false is auth.
if(holderObj.type1==true)
processDbStatement(holderObj.type2, holderObj.sqlquery);
else {
authCheck(holderObj.userName, holderObj.passWord);
if(!authCheck)
closeDbConnection();
}
}

//Send messages to client.
private void sendMessage(String message) {
// Send message to client
try {
ObjectOutputStream output = new ObjectOutputStream(connection.getOutputStream());
output.flush();

output.writeObject(message);
output.flush();
displayMessage("Message Sent:" + message);
}
catch (IOException ioException) {
displayMessage("\nError Sending Message: " + message);
}
}

//Send object to client
private void sendObject(Object holderObj) {
// Send object to client
try {
ObjectOutputStream output = new ObjectOutputStream(connection.getOutputStream());
output.writeObject(holderObj);
output.flush();
displayMessage("\nObject sent");
}
//Process problems sending object
catch (IOException ioException) {
displayMessage("\nError writing object");
}
}

//Close streams and socket.
private void closeSockConnection() {
displayMessage("Terminating connection");

try {
//output.close();
//input.close();
connection.close();
closeDbConnection();
this.userName = null;
this.passWord = null;
this.receiverId = 0;
this.authCheck = false;
}
catch (IOException ioException) {
displayMessage("I/O Error: " + ioException);
}
}

Client:

private void runClient() {
//Connect to sever and process messages from server.
try{
connectToServer();
getStreams();
processConnection();
}
//Server closed connection.
catch(EOFException eofException) {
//displayMessage"Client Terminated Connection");
}
//Process problems communicating with server.
catch (IOException ioException) {
//displayMessage"Communication Problem");
}
finally {
closeConnection();
}
}

//Connect to server
private void connectToServer() throws IOException {
//displayMessage("Attempting connection\n");

//Create Socket to make connection to sever.
client = new Socket(InetAddress.getByName(chatServer), 12345);
//Display connection information
//displayMessage("Connected to: " + client.getInetAddress().getHostName());
}

//Get streams to send and receive data.
private void getStreams() throws IOException {
//Set up output stream for objects.
ObjectOutputStream output = new ObjectOutputStream(client.getOutputStream());
output.flush(); //Flush outout buffer to send header information.

//Set up input stream for objects.
ObjectInputStream input = new ObjectInputStream(client.getInputStream());
//displayMessage("\nGot I/O streams\n");
}

//Close socket connection.
private void closeConnection() {
//displayMessage("\nClosing connection");

try {
ObjectOutputStream output = new ObjectOutputStream(client.getOutputStream());
output.close();
ObjectInputStream input = new ObjectInputStream(client.getInputStream());
input.close();
client.close();
authCheck=false;
}
catch(IOException ioException) {
ioException.printStackTrace();
}
}

//Send data to server.
private void sendObject(classHolderClient queryObj) {
try {
output.writeObject(queryObj);
output.flush();
//displayMessage("Please wait..");
}
//Process problems sending object.
catch (IOException ioException) {
//displayMessage("\nError writing object");
}
}

//Process connection with server.
private void processConnection() throws IOException {
try{
classHolderClient holderObj = new classHolderClient();
holderObj = (classHolderClient)input.readObject();
if(holderObj.type2==2) {
this.authCheck=holderObj.authCheck;
this.userName=holderObj.userName;
this.passWord=holderObj.passWord;
}
}
catch(ClassNotFoundException classNotFoundException) {
//displayMessage(classNotFoundException);
}
}

[mira yang]

I got the same problem. And i post a topic in Java � I/O and Streams
If you get a answer,please send a copy to me :[e-mail]
Thanks!

[mira yang]

Hello, I have got a answer to solve this problem:
The best way to create a dead lock is to try to read from both ends of a stream at the same time. I assume that the code for your server and your client are both attempting to get the ObjectInputStream before getting the ObjectOutputStream. Basically, all you have to do to fix this problem is put the getObjectOutputStream line BEFORE the getObjectInputStream line..
Hope this helps!