Code existing from 31.1 is listed below.

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import java.io.*;

import java.net.*;

import javafx.application.Application;

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.control.Button;

import javafx.scene.layout.GridPane;

import javafx.scene.layout.BorderPane;

import javafx.stage.Stage;

public class Client extends Application {

// Datastreams

DataOutputStream toServer = null;

DataInputStream fromServer = null;

//txtfield loan

private TextField tfAnnualInterestRate = new TextField();

private TextField tfNumberOfYears = new TextField();

private TextField tfLoanAmount = new TextField();

// Button for sending info

private Button btSubmit = new Button("Submit");

@Override

public void start(Stage primaryStage) {

BorderPane pane = new BorderPane();

// Alignment txtfields

tfAnnualInterestRate.setAlignment(Pos.BASELINE_RIGHT);

tfNumberOfYears.setAlignment(Pos.BASELINE_RIGHT);

tfLoanAmount.setAlignment(Pos.BASELINE_RIGHT);

// Information pane,grid

GridPane paneForLoanInfo = new GridPane();

paneForLoanInfo.add(new Label("Annual Interest Rate"), 0, 0);

paneForLoanInfo.add(tfAnnualInterestRate, 1, 0);

paneForLoanInfo.add(new Label("Number Of Years"), 0, 1);

paneForLoanInfo.add(tfNumberOfYears, 1, 1);

paneForLoanInfo.add(btSubmit, 2, 1);

paneForLoanInfo.add(new Label("Loan Amount"), 0, 2);

paneForLoanInfo.add(tfLoanAmount, 1, 2);

// Textarea

TextArea ta = new TextArea();

pane.setTop(paneForLoanInfo);

pane.setCenter(new ScrollPane(ta));

// Create a scene and place it in the stage

Scene scene = new Scene(pane, 500, 200);

primaryStage.setTitle("Loan Calculator, Client"); // Set the stage title

primaryStage.setScene(scene); // Place the scene in the stage

primaryStage.show(); // Display the stage

btSubmit.setOnAction(e -> {

try {

// Annual interest from field

double annualInterestRate = Double.parseDouble(

tfAnnualInterestRate.getText().trim());

int numberOfYears = Integer.parseInt(

tfNumberOfYears.getText().trim());

double loanAmount = Double.parseDouble(

tfLoanAmount.getText().trim());

// Transmit to server

toServer.writeDouble(annualInterestRate);

toServer.writeInt(numberOfYears);

toServer.writeDouble(loanAmount);

toServer.flush();

// Get payment from server

Double monthlyPayment = fromServer.readDouble();

Double totalPayment = fromServer.readDouble();

// Display to teat area

ta.appendText("Annual Interest Rate: " + annualInterestRate + ' ');

ta.appendText("Number Of Years: " + numberOfYears + ' ');

ta.appendText("Loan Amount: " + loanAmount + ' ');

ta.appendText("monthlyPayment: " + monthlyPayment + ' ');

ta.appendText("totalPayment: " + totalPayment + ' ');

}

catch (IOException ex) {

System.err.println(ex);

}

});

try {

// Socket connection

Socket clientSocket = new Socket("localhost", 8000);

// Input stream

fromServer = new DataInputStream(clientSocket.getInputStream());

// Output stream

toServer = new DataOutputStream(clientSocket.getOutputStream());

}

catch (IOException ex) {

ta.appendText(ex.toString() + ' ');

}

}

}

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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

public void start(Stage primaryStage) {

// Txt area

TextArea tas = new TextArea();

// Create a scene and place it in the stage

Scene scene = new Scene(new ScrollPane(tas), 500, 200);

primaryStage.setTitle("Loan Calculator, Server"); // Set the stage title

primaryStage.setScene(scene); // Place the scene in the stage

primaryStage.show(); // Display the stage

new Thread(() -> {

try {

// Serversocket

ServerSocket serverSocket = new ServerSocket(8000);

Platform.runLater(() ->

tas.appendText("Server started at " + new Date() + ' '));

// Connection request

Socket socket = serverSocket.accept();

// Input stream

DataInputStream inputFromClient = new DataInputStream(socket.getInputStream());

// Outputstream

DataOutputStream outputToClient = new DataOutputStream(socket.getOutputStream());

while

(true) {

Date dateClientConnected = new Date();

// Get loan info form client

double annualInterestRate = inputFromClient.readDouble();

int numberOfYears = inputFromClient.readInt();

double loanAmount = inputFromClient.readDouble();

// Compute payments

double monthlyInterestRate = annualInterestRate / 1200;

double monthlyPayment = loanAmount * monthlyInterestRate / (1 - 1 / Math.pow(1 + monthlyInterestRate, numberOfYears * 12));

double totalPayment = monthlyPayment * numberOfYears * 12;

// Transmit to client

outputToClient.writeDouble(monthlyPayment);

outputToClient.writeDouble(totalPayment);

Platform.runLater(() -> {

tas.appendText("Connected to a client at " + dateClientConnected + ' ');

tas.appendText("Annual Interest Rate: " + annualInterestRate + ' ');

tas.appendText("Number Of Years: " + numberOfYears + ' ');

tas.appendText("Loan Amount: " + loanAmount + ' ');

tas.appendText("monthlyPayment: " + monthlyPayment + ' ');

tas.appendText("totalPayment: " + totalPayment + ' ');

});

}}

catch(IOException ex) {

ex.printStackTrace();

}

}).start();

}

}

Sections 31.3 and 31.4 *31.3 (Loan server for multiple clients) Revise Programming Exercise 31.1 to write a server for multiple clients. Sections 31.3 and 31.4 *31.3 (Loan server for multiple clients) Revise Programming Exercise 31.1 to write a server for multiple clients