Drag a rectangle on a JFrame in Java

What you need to do is save the previously drawn rectangle in some kind of data structure, so you can do it again later.

This code (sorry for the length, do something similar to what you describe). To use it, just click JPanelinside JFrame.

public class DrawPane extends JPanel {

    private List<DrawnShape> drawings;
    private DrawnShape curShape;

    public DrawPane() {
        drawings = new ArrayList<DrawnShape>();
        setBackground(Color.WHITE);
        setPreferredSize(new Dimension(300, 300));
        addMouseListener(clickListener);
        addMouseMotionListener(moveListener);
    }

    @Override
    protected void paintComponent(Graphics g2) {
        super.paintComponent(g2);
        Graphics2D g = (Graphics2D) g2;
        for (DrawnShape s : drawings) {
            s.draw(g);
        }
        g.setColor(Color.BLACK);
        g.setStroke(new BasicStroke(2));

        if (curShape == null)
            return;
        curShape.draw(g);
    }

    private MouseListener clickListener = new MouseAdapter() {

        @Override
        public void mousePressed(MouseEvent e) {
            curShape = new DrawnShape(e.getPoint(), e.getPoint());
        }

        @Override
        public void mouseReleased(MouseEvent e) {
            drawings.add(new DrawnShape(curShape.getClickP(), e.getPoint()));
            curShape = null;
        }
    };

    private MouseMotionListener moveListener = new MouseMotionListener() {

        @Override
        public void mouseDragged(MouseEvent e) {
            curShape = new DrawnShape(curShape.getClickP(), e.getPoint());
            repaint();
        }
        @Override
        public void mouseMoved(MouseEvent e) {
        }
    };
}

class DrawnShape {

    private Point p1, p2;

    public DrawnShape(Point p1, Point p2) {
        this.p1 = p1;
        this.p2 = p2;
    }

    public Point getClickP() {
        return p1;
    }

    public void draw(Graphics2D g) {
        g.drawLine(p1.x, p1.y, p2.x, p1.y);
        g.drawLine(p1.x, p1.y, p1.x, p2.y);
        g.drawLine(p2.x, p2.y, p2.x, p1.y);
        g.drawLine(p2.x, p2.y, p1.x, p2.y);
    }
}