Sending data with ServerSocket

Newbie & Debugging Questions
#1

So I have began with doing a turn based rpg game, which going to have multiplayer, but I have run into a problem. I don’t know how to send data to a socket without closing it, sure I could make the clients re-connect to the ServerSocket to receive new data, but that seems wrong to me, or is it?

Some code I tested with

public void sendMessage(Socket socket, String message){
        try{
            OutputStream out = socket.getOutputStream();
            out.write(message.getBytes());
            out.close();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
    
    public void sendMessage(String message){
        for(Socket s : players)
            sendMessage(s, message);
    }

public class Test {    
    public static void main(String[] args) throws Exception{
        Server server =  new Server(1233);;
        Client client = new Client("127.0.0.1", 1233); 
        
        server.sendMessage("Data 1");
        server.sendMessage("Data 2");
        
        Thread.sleep(1000);
        System.exit(0);
    }
}