In my java code why am I still recieving this error code: Error: Could not find or load main class Shapes.Shape

Caused by: java.lang.NoClassDefFoundError: javafx$/$application$/$Application$.$ import javafx.application.Application;

import javafx.geometry.Insets;

import javafx.scene.Scene;

import javafx.scene.Group;

import javafx.scene.layout.GridPane;

import javafx.scene.layout.StackPane;

import javafx.scene.shape.Line;

import javafx.scene.shape.Circle;

import javafx.scene.shape.Rectangle;

import javafx.scene.paint.Color;

import javafx.stage.Stage;

$//$

public class Shape extends Application $\{$

$//$defining the X variable

private static final int x $=50$;

@Override

public void start$($Stage primaryStage$)\{$

$//$created rectangle

$//$set properties

Rectangle angle $=$ new Rectangle$()$;

angle.setX$(50)$;

angle.setY$(50)$;

angle.setHeight$(2*$ x$)$;

angle.setWidth$(2*$ x$)$;

angle.setStroke$($Color$.$BLUE$)$;

angle.setFill$($Color$.$BLUE$)$;

angle.setStrokeWidth$(3)$;

$//$created circle

$//$set properties

Circle c $=$ new Circle$($x$)$;

c$.$setStroke$($Color$.$RED$)$;

c$.$setFill$($Color$.$RED$)$;

c$.$setStrokeWidth$(3)$;

Line line$11=$ new Line$(-$x $/1\mathrm{.}5,-$x $/2\mathrm{.}5,$ x $/1\mathrm{.}5,-$x $/2\mathrm{.}5)$;

Line line$12=$ new Line$(0,-$x$,0,$ x$)$;

line$11.$setStroke$($Color$.$GREEN$)$;

line$11.$setStrokeWidth$(6)$;

line$12.$setStroke$($Color$.$GREEN$)$;

line$12.$setStrokeWidth$(6)$;

StackPane lines $=$ new StackPane$()$;

GridPane pane $=$ new GridPane$()$;

pane.setPadding$($new Insets$(10,10,10,10))$;

pane.add$($lines$,2,2)$;

pane.add$($angle$,0,0)$;

pane.add$($c$,1,1)$;

pane.add$($new Group$(),2,2)$;

Scene scene $=$ new Scene$($pane$)$;

primaryStage.setTitle$("$Shapes in Grid"$)$;

primaryStage.setScene$($scene$)$;

primaryStage.show$()$;

primaryStage.setResizable$($false$)$;

$\}$

public static void main$($String$[]$ args$)\{$

launch$($args$)$;

$\}$

$\}$