Example of sending a String through a Socket in Java.

SendStringOverSocket.java

import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;

public class Client {
    public static void main(String[] args) throws IOException {
        // need host and port, we want to connect to the ServerSocket at port 7777
        Socket socket = new Socket("localhost", 7777);
        System.out.println("Connected!");

        // get the output stream from the socket.
        OutputStream outputStream = socket.getOutputStream();
        // create a data output stream from the output stream so we can send data through it
        DataOutputStream dataOutputStream = new DataOutputStream(outputStream);

        System.out.println("Sending string to the ServerSocket");

        // write the message we want to send
        dataOutputStream.writeUTF("Hello from the other side!");
        dataOutputStream.flush(); // send the message
        dataOutputStream.close(); // close the output stream when we're done.

        System.out.println("Closing socket and terminating program.");
        socket.close();
    }
}


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

public class Server {
    public static void main(String[] args) throws IOException {
        // don't need to specify a hostname, it will be the current machine
        ServerSocket ss = new ServerSocket(7777);
        System.out.println("ServerSocket awaiting connections...");
        Socket socket = ss.accept(); // blocking call, this will wait until a connection is attempted on this port.
        System.out.println("Connection from " + socket + "!");

        // get the input stream from the connected socket
        InputStream inputStream = socket.getInputStream();
        // create a DataInputStream so we can read data from it.
        DataInputStream dataInputStream = new DataInputStream(inputStream);

        // read the message from the socket
        String message = dataInputStream.readUTF();
        System.out.println("The message sent from the socket was: " + message);

        System.out.println("Closing sockets.");
        ss.close();
        socket.close();
    }
}

//Server Output
/*
ServerSocket awaiting connections...
Connection from Socket[addr=/127.0.0.1,port=62085,localport=7777]!
The message sent from the socket was: Hello from the other side!
Closing sockets.
*/

// Client Output
/*
Connected!
Sending string to the ServerSocket
Closing socket and terminating program.
*/