ClientMain.java

import java.util.Scanner;

public class ClientMain {

    public static void main(String[] args) {

        Client client = new Client();
        Scanner sc = new Scanner(System.in);

        while(true) {

            System.out.println("\n1. Connect to Server");
            System.out.println("2. Send Message");
            System.out.println("3. Close Client");

            int choice = sc.nextInt();
            sc.nextLine();

            switch(choice) {

                case 1:
                    client.connect();

                    // listen to server messages
                    new Thread(() -> client.receive()).start();
                    break;

                case 2:
                    System.out.print("Enter message: ");
                    String msg = sc.nextLine();
                    client.send(msg);
                    break;

                case 3:
                    client.close();
                    sc.close();
                    return;

            }
        }

    }
}