Javafx - Tabuada V

Quando criei esta tabuada utilizei originalmente
uma interface do próprio dos, utilizando a classe J
que possui métodos para formatações dos textos na tela.
Por isso muita gente não pode testar.
Agora eu trago a mesma tabuada só que desta vez,
a impressão é feita numa tela gráfica com os recursos
da poderosa biblioteca javafx.

veja abaixo uma imagem do programa em execução:

Veja abaixo o código do programa:

import javafx.application.Application;

import javafx.collections.ObservableList;

import javafx.scene.Group;

import javafx.scene.Node;

import javafx.scene.Scene;

import javafx.scene.paint.Color;

import javafx.scene.text.Font;

import javafx.scene.text.FontWeight;

import javafx.stage.Stage;

import javafx.scene.canvas.Canvas;

import javafx.scene.canvas.GraphicsContext;

import javafx.scene.control.Button;

import javafx.scene.layout.Pane;

import javafx.concurrent.Task;

import javafx.event.ActionEvent;

import javafx.event.EventHandler;

public class PROJETO extends Application {

     static String str   = "";

     static String str_1 = "";

     static String str_2 = "";

     static String str_4 = "x";

     static String str_5 = "=";

     static Stage  stage;

     Scene              scene;

     static Pane        root     = new Pane ( );

     static Canvas canvas = new Canvas ( 700, 540 );

     static GraphicsContext ctx = canvas.getGraphicsContext2D ( );

     static int x = 0, k = 0, w = 0, y = 1, i = 0, j = 0, m = 0;

     static int x_1 = 0, x_2 = 0, x_3 = 0, x_4 = 0, x_5 = 0;

     // ///////////////////////////////////////////////////////////////////

     public static  Node But_ton_1 ( ) {

         Button btn_1 = new Button ( "ok" );

         btn_1.setPrefWidth ( 50 );// Largura do botão

         btn_1.setLayoutX ( 80 );// Posição do botão

         btn_1.setPrefHeight ( 20 );// altura do botão

         btn_1.setLayoutY ( 480 );// //Posição do botão

         btn_1.setOnAction ( new EventHandler < ActionEvent > ( ) {

              @Override

              public void handle ( ActionEvent event ) {

                   int b = 0;

                   b = 1;

                   Sleep ( 1800, b );

                   b = 2;

                   Sleep ( 2800, b );

              }

         } );

         root.getChildren ( ).add ( btn_1 );

         return btn_1;

     }

     // ///////////////////////////////////////////////////////////////////

     public static  Node But_ton_2 ( ) {

         Button btn_2 = new Button ( "sair" );

         btn_2.setPrefWidth ( 50 );// Largura do botão

         btn_2.setLayoutX ( 570 );// Posição do botão

         btn_2.setPrefHeight ( 20 );// altura do botão

         btn_2.setLayoutY ( 480 );// //Posição do botão

         btn_2.setOnAction ( new EventHandler < ActionEvent > ( ) {

              @Override

              public void handle ( ActionEvent event ) {

                   System.exit ( 0 );

              }

         } );

         root.getChildren ( ).add ( btn_2 );

         return btn_2;

     }

     // ///////////////////////////////////////////////////////////////////

     //Chamando uma função depois de um certo tempo

     public static void Tempo_2 ( ) {

         ctx.setFill ( Color.GREEN );

         ctx.fillText ( "MUITO OBRIGADO", 280, 500 );

     }

     public static void Tempo_1 ( ) {

         ctx.setFill ( Color.BLUE );

         ctx.fillText ( "Por: Samuel Lima", 280, 90 );

     }

     public static int Sleep ( int x, int k ){

         Task < Integer > close = new Task < Integer > ( ) {

              @Override

              protected Integer call ( ) throws Exception {

                   Thread.sleep ( x );

                   return null;

              }

         };     

         close.setOnSucceeded ( c -> {

              if ( k == 1 )

                   Tempo_1 ( );

              if ( k == 2 )

                   Tempo_2 ( );

         } );

         new Thread ( close ).start ( );

         return 0;

     }

     @Override

     public void start ( Stage stage ) throws InterruptedException {

         ctx.setStroke ( Color.RED );

         ctx.setLineWidth ( 22.0 );

         ctx.strokeRoundRect ( 10, 10, 680, 520, 10, 10 );

         root.getChildren ( ).add ( canvas );

         Scene scene = new Scene ( root );

         stage.setTitle ( "TABUADA V - LINGUAGEM JAVA" );

         ctx.setFont ( Font.font ( "Arial", FontWeight.BOLD, 15 ) );

         ctx.setFill ( Color.RED );

         ctx.fillText ( "TABUADA V - LINGUAGEM JAVA", 220, 60 );

         ObservableList < Node > content = ( ( Pane ) scene.getRoot ( ) )

                   .getChildren ( );

         stage.setScene ( scene );

         stage.show ( );

         content.add ( Line ( ) );

     }

     public static Node Line ( ) {

         Group z = new Group ( );

         do {

              int p_1 = 120;

              int p_2 = 240;

              int p_3 = 360;

              int p_4 = 480;

              if ( y == 1 ){

                   j = 100;

                   x_1 = 70;

                   x_2 = 110;

                   x_3 = 150;

                   x_4 = 90;

                   x_5 = 130;

                   m = 115;

              }

              if ( y == 2 ){

                   j = 100;

                   x_1 = 70 + p_1;

                   x_2 = 110 + p_1;

                   x_3 = 150 + p_1;

                   x_4 = 90 + p_1;

                   x_5 = 130 + p_1;

                   m = 115;

              }

              if ( y == 3 ){

                   j = 100;

                   x_1 = 70 + p_2;

                   x_2 = 110 + p_2;

                   x_3 = 150 + p_2;

                   x_4 = 90 + p_2;

                   x_5 = 130 + p_2;

                   m = 115;

              }

              if ( y == 4 ){

                   j = 100;

                   x_1 = 70 + p_3;

                   x_2 = 110 + p_3;

                   x_3 = 150 + p_3;

                   x_4 = 90 + p_3;

                   x_5 = 130 + p_3;

                   m = 115;

              }

              if ( y == 5 ){

                   j = 100;

                   x_1 = 70 + p_4;

                   x_2 = 110 + p_4;

                   x_3 = 150 + p_4;

                   x_4 = 90 + p_4;

                   x_5 = 130 + p_4;

                   m = 115;

              }

              if ( y == 6 ){

                   j = 285;

                   x_1 = 70;

                   x_2 = 110;

                   x_3 = 150;

                   x_4 = 90;

                   x_5 = 130;

                   m = 300;

              }

              if ( y == 7 ){

                   j = 285;

                   x_1 = 70 + p_1;

                   x_2 = 110 + p_1;

                   x_3 = 150 + p_1;

                   x_4 = 90 + p_1;

                   x_5 = 130 + p_1;

                   m = 300;

              }

              if ( y == 8 ){

                   j = 285;

                   x_1 = 70 + p_2;

                   x_2 = 110 + p_2;

                   x_3 = 150 + p_2;

                   x_4 = 90 + p_2;

                   x_5 = 130 + p_2;

                   m = 300;

              }

              if ( y == 9 ){

                   j = 285;

                   x_1 = 70 + p_3;

                   x_2 = 110 + p_3;

                   x_3 = 150 + p_3;

                   x_4 = 90 + p_3;

                   x_5 = 130 + p_3;

                   m = 300;

              }

              if ( y == 10 ){

                   j = 285;

                   x_1 = 70 + p_4;

                   x_2 = 110 + p_4;

                   x_3 = 150 + p_4;

                   x_4 = 90 + p_4;

                   x_5 = 130 + p_4;

                   m = 300;

              }

              x = 1;

              for ( i = 0; i < 10; i++ ) {

                   do {

                        k = y;

                        w = k * x;

                        if ( y <= 10 ) {

                            str = str += ("\n");

                            str = str += k;

                        }

                        if ( x <= 10){

                            str_1 = str_1 += ("\n");

                            str_1 = str_1 += x;

                        }

                        if ( x < 10){

                            str_4 += ("\n");

                            str_4 += "x";

                        }

                        if ( x < 10){

                            str_5 += ("\n");

                            str_5 += "=";

                        }

                        if ( w <= 100){

                            str_2 += ("\n");

                            str_2 += w;

                        }

                        ctx.setFill ( Color.BLACK );

                        ctx.fillText ( str, x_1, j );

                        ctx.setFill ( Color.BLACK );

                        ctx.fillText ( str_1, x_2, j );

                        ctx.setFill ( Color.RED );

                        ctx.fillText ( str_2, x_3, j );

                        ctx.setFill ( Color.BLACK );

                        ctx.fillText ( str_4, x_4, m );

                        ctx.setFill ( Color.BLUE );

                        ctx.fillText ( str_5, x_5, m );

                        i++;

                        x++;

                   } while ( x <= 10 );

              }

              y++;

              str   = "";

              str_1 = "";

              str_2 = "";

              str_4 = "x";

              str_5 = "=";

         } while ( y <= 10 );

         But_ton_1 ( );

         But_ton_2 ( );

         return z;

     }

     // //////////////////////////////////////////////////////////////////////////

     public static void main ( String [ ] args ) {

         Application.launch ( args );

     }

}