package testcase;

import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

import serialportutil.AbstractSerialCommand;
import serialportutil.CommandBatch;
import serialportutil.SerialPortConf;

class ClientServiceThread extends Thread {
    SimpleServer simpleServer;
    Socket clientSocket;
    int clientID = -1;
    boolean running = true;

    ClientServiceThread(SimpleServer simpleServer, Socket s, int i) {
        this.simpleServer = simpleServer;
        this.clientSocket = s;
        this.clientID = i;
    }

    public void run() {
        try {
            InputStream in = clientSocket.getInputStream();
            simpleServer.addOutputStream(clientSocket.getOutputStream());
            int cmd;
            try {
                while ((running && (cmd = in.read()) > 0)) {
                    simpleServer.sendCommand(cmd, 0);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

public class SimpleServer extends AbstractSerialCommand {
    protected void setup() {
        // Setup serial
        setSerialPortConf(new SerialPortConf("COM15", 115200, 8, 1, 0));

        // Set serial port,replace '\r\n' with '\n' (telnet)
        setSerialPortCRAsLFCR(true);
    }

    @Override
    protected void processCommand() throws Exception {
        @SuppressWarnings("resource")
        ServerSocket serverSocket = new ServerSocket(88);
        int id = 0;
        while (true) {
            Socket clientSocket = serverSocket.accept();
            ClientServiceThread cliThread = new ClientServiceThread(this, clientSocket, id++);
            cliThread.start();
        }
    }

    public static void main(String[] args) throws Exception {
        CommandBatch.addClazz(SimpleServer.class);
        CommandBatch.go();
    }
}

Using telnet connect server, and interactive with remote serial port.