How to run Server/Client program in JGrasp for Java?

Question

So the code you see below is from a powerpoint my professor gave us. It should be correct, because our textbook made these powerpoints. This code below is an example code of a client sending a circle radius to a server. The server calculates the circle's area. The issue is, I can't test the code, because I need both the server and client open simultaneously. How do I test the code if both can't be running? I am using JGRASP by the way.

Server Class

import java.io.*;
import java.net.*;
import java.util.Date;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Scene;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.TextArea;
import javafx.stage.Stage;

public class Server extends Application {
  @Override // Override the start method in the Application class
  public void start(Stage primaryStage) {
    // Text area for displaying contents
    TextArea ta = new TextArea();

    // Create a scene and place it in the stage
    Scene scene = new Scene(new ScrollPane(ta), 450, 200);
    primaryStage.setTitle("Server"); // Set the stage title
    primaryStage.setScene(scene); // Place the scene in the stage
    primaryStage.show(); // Display the stage

    new Thread( () -> {
      try {
        // Create a server socket
        ServerSocket serverSocket = new ServerSocket(8000);
        Platform.runLater(() ->
          ta.appendText("Server started at " + new Date() + '\n'));

        // Listen for a connection request
        Socket socket = serverSocket.accept();

        // Create data input and output streams
        DataInputStream inputFromClient = new DataInputStream(
          socket.getInputStream());
        DataOutputStream outputToClient = new DataOutputStream(
          socket.getOutputStream());

        while (true) {
          // Receive radius from the client
          double radius = inputFromClient.readDouble();

          // Compute area
          double area = radius * radius * Math.PI;

          // Send area back to the client
          outputToClient.writeDouble(area);

          Platform.runLater(() -> {
            ta.appendText("Radius received from client: " 
              + radius + '\n');
            ta.appendText("Area is: " + area + '\n'); 
          });
        }
      }
      catch(IOException ex) {
        ex.printStackTrace();
      }
    }).start();
  }

  /**
   * The main method is only needed for the IDE with limited
   * JavaFX support. Not needed for running from the command line.
   */
  public static void main(String[] args) {
    launch(args);
  }
}

Client Class

import java.io.*;
import java.net.*;
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class Client extends Application {
  // IO streams
  DataOutputStream toServer = null;
  DataInputStream fromServer = null;

  @Override // Override the start method in the Application class
  public void start(Stage primaryStage) {
    // Panel p to hold the label and text field
    BorderPane paneForTextField = new BorderPane();
    paneForTextField.setPadding(new Insets(5, 5, 5, 5)); 
    paneForTextField.setStyle("-fx-border-color: green");
    paneForTextField.setLeft(new Label("Enter a radius: "));

    TextField tf = new TextField();
    tf.setAlignment(Pos.BOTTOM_RIGHT);
    paneForTextField.setCenter(tf);

    BorderPane mainPane = new BorderPane();
    // Text area to display contents
    TextArea ta = new TextArea();
    mainPane.setCenter(new ScrollPane(ta));
    mainPane.setTop(paneForTextField);

    // Create a scene and place it in the stage
    Scene scene = new Scene(mainPane, 450, 200);
    primaryStage.setTitle("Client"); // Set the stage title
    primaryStage.setScene(scene); // Place the scene in the stage
    primaryStage.show(); // Display the stage

    tf.setOnAction(e -> {
      try {
        // Get the radius from the text field
        double radius = Double.parseDouble(tf.getText().trim());

        // Send the radius to the server
        toServer.writeDouble(radius);
        toServer.flush();

        // Get area from the server
        double area = fromServer.readDouble();

        // Display to the text area
        ta.appendText("Radius is " + radius + "\n");
        ta.appendText("Area received from the server is "
          + area + '\n');
      }
      catch (IOException ex) {
        System.err.println(ex);
      }
    });

    try {
      // Create a socket to connect to the server
      Socket socket = new Socket("localhost", 8000);
      // Socket socket = new Socket("130.254.204.36", 8000);
      // Socket socket = new Socket("drake.Armstrong.edu", 8000);

      // Create an input stream to receive data from the server
      fromServer = new DataInputStream(socket.getInputStream());

      // Create an output stream to send data to the server
      toServer = new DataOutputStream(socket.getOutputStream());
    }
    catch (IOException ex) {
      ta.appendText(ex.toString() + '\n');
    }
  }

  /**
   * The main method is only needed for the IDE with limited
   * JavaFX support. Not needed for running from the command line.
   */
  public static void main(String[] args) {
    launch(args);
  }
}

Answer 1

Run either one of them from the command line, and the other from jGRASP.