Java - Bidirectional Data transfer using TCP

ServerThread.java


import java.io.*;
import java.net.*;

public class ServerThread implements Runnable {
ServerSocket serverSocket = null;
Socket socket = null;
BufferedReader readFromClient = null;
BufferedReader readFromServer = null;
PrintWriter writeToClient = null;
String message = null;

public ServerThread() {
try {
serverSocket = new ServerSocket(4444);
System.out.println("Waiting for connection...");
socket = serverSocket.accept();
System.out.println("Connection accepted...");

readFromClient = new BufferedReader(
new InputStreamReader(
socket.getInputStream()));
writeToClient = new PrintWriter(
socket.getOutputStream(), true);
readFromServer = new BufferedReader(
new InputStreamReader(
System.in));

new Thread(this).start();

while(true) {
message = readFromServer.readLine();
writeToClient.println(message);
writeToClient.flush();
if(message.equalsIgnoreCase("exit")) {
System.exit(0);
}
}

} catch(IOException exp) {
exp.printStackTrace();
}
}

public void run() {
try {
while(true) {
String msg = readFromClient.readLine();
if(!msg.equalsIgnoreCase("exit")) {
System.out.println(msg);
} else {
System.exit(0);
}
}
} catch(Exception exp) {
exp.printStackTrace();
}
}
}

Server.java


public class Server {
public static void main(String[] args) {
new ServerThread();
}
}

ClientThread.java

import java.io.*;
import java.net.*;

public class ClientThread implements Runnable {
Socket socket = null;
BufferedReader readFromClient = null;
BufferedReader readFromServer = null;
PrintWriter writeToServer = null;
String message = null;

public ClientThread(Socket socket) {
try {
this.socket = socket;
readFromServer = new BufferedReader(
new InputStreamReader(
socket.getInputStream()));
writeToServer = new PrintWriter(
socket.getOutputStream(), true);
readFromClient = new BufferedReader(
new InputStreamReader(System.in));

new Thread(this).start();

while(true) {
message = readFromClient.readLine();
writeToServer.println(message);
writeToServer.flush();
if(message.equalsIgnoreCase("exit")) {
System.exit(0);
}
}
} catch(IOException exp) {
exp.printStackTrace();
}
}


public void run() {
try {
while(true) {
String msg = readFromServer.readLine();
if(!msg.equalsIgnoreCase("exit")) {
System.out.println(msg);
} else {
System.exit(0);
}
}
} catch(Exception exp) {
exp.printStackTrace();
}
}
}


Client.java

import java.io.*;
import java.net.*;

public class Client {
Socket socket = null;


public Client() {
try {
socket = new Socket("localhost",4444);
new ClientThread(socket);
} catch(UnknownHostException exp) {
exp.printStackTrace();
} catch(IOException exp) {
exp.printStackTrace();
}
}

public static void main(String[] args) {
new Client();
}
}