Graphics上下文是共享资源，也就是说，在单个绘制周期中，所有组件都获得相同的Graphics上下文。您对Graphics上下文所做的任何更改也会得到维护（或在相同转换的情况下复合）。因此，这意味着，每次调用Graphics#rotate时，您实际上是在复合任何可能在其上执行的先前旋转。

您需要通过两种方式更改代码…

1. 你需要一个独立的更新周期，独立于绘制周期
2. 在应用任何转换之前创建Graphics上下文的本地副本

比如说…

矩形成为主要的驱动程序/引擎。它负责管理实体并在每个周期更新它们。通常，我会使用某种接口来描述其他情况下可能能够使用的功能，但你明白了

public class Rectangles {

    public static void main(String[] args) throws Exception {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }
                Rectangles game = new Rectangles();
                game.play();
            }
        });
    }

    public void play() {

        Board board = new Board(this);

        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(board);
        f.pack();
        f.setLocation(200, 200);
        f.setVisible(true);
        Timer timer = new Timer(40, new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                updateRectangles();
                board.repaint();
                lastTime = System.nanoTime();
            }
        });
        timer.start();
    }

    public Rectangles() {
        rectangle_2 = new Rectangle_2();
        rectangles = new ArrayList<Rectangle_2>();
    }

    protected void updateRectangles() {
        boolean first = (lastTime == -1L);
        double elapsedTime = System.nanoTime() - lastTime;
        elapsedTime = (first ? 0.0f : (float) elapsedTime / 1e9f);

        ticks++;
        if (ticks <= 1 || ticks % 100 == 0) {
            Rectangle_2 rectangle = new Rectangle_2();
            rectangles.add(rectangle);
        }

        rotateRectangles();
        moveRectangles(elapsedTime);


        for (int i = 0; i < rectangles.size(); i++) {
            Rectangle_2 rectangle = rectangles.get(i);
            if (rectangle.getX() < -75) {
                rectangles.remove(i);
                i--;
            }
        }
    }

    public void drawRectangles(Graphics2D g) {
        for (Rectangle_2 rectangle : rectangles) {
            rectangle.drawRectangle(g);
        }
    }

    protected void rotateRectangles() {
        for (Rectangle_2 rectangle : rectangles) {
            rectangle.rotateRectangle();
        }
    }

    protected void moveRectangles(double elapsedTime) {
        for (Rectangle_2 rectangle : rectangles) {
            rectangle.move(10 * elapsedTime);
        }
    }

    private long lastTime = -1L;
    private Rectangle_2 rectangle_2;
    private int ticks = 0;
    private ArrayList<Rectangle_2> rectangles;
}

Board只不过是一个可以渲染实体的表面

public class Board extends JPanel {

    public Board(Rectangles engine) {
        game = engine;
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(400, 400);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        game.drawRectangles((Graphics2D) g);
    }

    private Rectangles game;
}

Rectangle_2是一个简单的信息容器，它知道如何在有机会时自行绘制。您会注意到移动和旋转方法只是更新状态，它们不做任何其他事情。

首先创建提供的Graphics2D上下文的副本，然后应用它的更改并呈现矩形，完成后，它调用dispos来处理副本

public class Rectangle_2 {

    public Rectangle_2() {
        x = 0;
        y = 200;
        rectangle = new Rectangle((int) x, (int) y, 25, 25);
    }

    public void drawRectangle(Graphics2D g) {
        Graphics2D g2 = (Graphics2D) g.create();
        g2.rotate(angle, rectangle.getX() + rectangle.getWidth() / 2, rectangle.getY() + rectangle.getHeight() / 2);
        g2.setColor(Color.red);
        g2.draw(rectangle);
        g2.dispose();
    }

    public void rotateRectangle() {
        angle += 0.001;
    }

    public void move(double elapsedTime) {
        x = x + elapsedTime;
        rectangle.setLocation((int) x, (int) y);
    }

    public boolean collides(Rectangle r) {
        return r.intersects(rectangle);
    }

    @Override
    public String toString() {
        return "Pipe [x = " + x + ", y = " + y + ", rectangle = " + rectangle + "]";
    }

    public Rectangle getRectangle() {
        return rectangle;
    }

    public double getX() {
        return x;
    }

    private double x;
    private double y;
    private double angle = 0;
    private Rectangle rectangle;
}