@@ -0,0 +1,908 @@
+package game.invader;%0A%0Aimport java.awt.*;%0Aimport javax.swing.*;%0A%0Apublic class Invader extends JPanel %7B%0A%0A    public static final int DEFAULT_STEP = 1;%0A%0A    public static final Color DEFAULT_BACKGROUND = Color.MAGENTA;%0A%0A    public static final int WIDTH = 10;%0A    public static final int HEIGHT = 10;%0A%0A    int step = DEFAULT_STEP;%0A%0A    int x = 0;%0A%0A    int y = 0;%0A%0A    String content;%0A%09%0A    public int getStep() %7B%0A        return step;%0A    %7D%0A%0A    public Invader setStep(int step) %7B%0A        this.step = step;%0A        return this;%0A    %7D%0A%0A    public void setX(int x) %7B%0A        System.out.println(x);%0A        this.x = x;%0A    %7D%0A%0A    public Invader moveDown() %7B%0A        y += step;%0A        repaint();%0A        return this;%0A    %7D%0A%0A    public void paintComponent(Graphics graphics) %7B%0A        super.paintComponent(graphics);%0A        graphics.setColor(Color.MAGENTA);%0A        graphics.fillRect(x, y, WIDTH, HEIGHT);%0A    %7D%0A%7D%0A

Add Invader class