Java Network exercise: client and server - client send something to server

Refer to my old post of "Java exercise - Implement client and server to communicate using Socket", setup bold server and client. The server reply something to client once connected.

It's modified, client connect to server and send something. In server side, wait connected and print the received text to screen.


host.java

import java.io.BufferedReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.io.OutputStream;
import java.io.PrintStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.logging.Level;
import java.util.logging.Logger;

class host
{
    public static void main(String srgs[])
    {   
        ServerSocket serverSocket = null;
        Socket socket = null;
        BufferedReader bufferedReader = null;
        PrintStream printStream = null;
        
        try{
            serverSocket = new ServerSocket(0);
            System.out.println("I'm waiting here: " 
                + serverSocket.getLocalPort());            
                                
            socket = serverSocket.accept();
            System.out.println("from " + 
                socket.getInetAddress() + ":" + socket.getPort());
            
            InputStreamReader inputStreamReader = 
                new InputStreamReader(socket.getInputStream());
            bufferedReader = new BufferedReader(inputStreamReader);
            
            String line;
            while((line=bufferedReader.readLine()) != null){
                System.out.println(line);
            }
        }catch(IOException e){
            System.out.println(e.toString());
        }finally{
            if(bufferedReader!=null){
                try {
                    bufferedReader.close();
                } catch (IOException ex) {
                    System.out.print(ex.toString());
                }
            }
            
            if(printStream!=null){
                printStream.close();
            }
            
            if(socket!=null){
                try {
                    socket.close();
                } catch (IOException ex) {
                    System.out.print(ex.toString());
                }
            }
        }
    }
}

client.java

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;
import java.net.UnknownHostException;

public class client {

    public static void main(String args[])
    { 
        if(args.length != 2){
            System.out.println("usage: java client <port> <something>");
            System.exit(1);
        }
        
        int port = isParseInt(args[0]);
        if(port == -1){
            System.out.println("usage: java client <port> <something>");
            System.out.println("<port>: integer");
            System.exit(1);
        }
        
        try{
            //IP is hard coded, Local Loopback = "127.0.0.1"
            //port is user entry
            Socket socket = new Socket("127.0.0.1", port);

            
            //Send msg to server
            OutputStream outputStream = socket.getOutputStream();
            PrintStream printStream = new PrintStream(outputStream);
            printStream.print(args[1]);
                
            socket.close();

        }catch(UnknownHostException e){
            System.out.println(e.toString());
        }catch(IOException e){
            System.out.println(e.toString());
        }

    }
    
    private static int isParseInt(String str){
        
        int num = -1;
        try{
             num = Integer.parseInt(str);
        } catch (NumberFormatException e) {
        }
        
        return num;
    }
    
}

It's Android version of the Client.

Next:
- bi-direction communication, between echo server and client