Java program to demonstrate JavaFX Drawing Lines.

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class SimpleLinesEx extends Application {

      public void start(Stage stage) {

        initUI(stage);
    }

    private void initUI(Stage stage) {

        Pane root = new Pane();

        Canvas canvas = new Canvas(300, 300);
        GraphicsContext gc = canvas.getGraphicsContext2D();
        drawLines(gc);

        root.getChildren().add(canvas);

        Scene scene = new Scene(root, 300, 250, Color.WHITESMOKE);

        stage.setTitle("Lines");
        stage.setScene(scene);
        stage.show();
    }

    private void drawLines(GraphicsContext gc) {

        gc.beginPath();
        gc.moveTo(30.5, 30.5);
        gc.lineTo(150.5, 30.5);
        gc.lineTo(150.5, 150.5);
        gc.lineTo(30.5, 30.5);
        gc.stroke();
    }

    public static void main(String[] args) {
        launch(args);
    }
}