Thread.sleep() not working

Question

Whilst trying to make a gamecharacter jump in java, I tried to use Thread.sleep() to make an image move up 5 pixels, then wait for eg 100 miliseconds, then move up 5 pixels again, etc.

Instead, when the image needs to make 5 steps up of 5 pixels each, and wait 100 miliseconds everytime, it waits 500 miliseconds and moves up 25 pixels.

I can't explain this behaviour and there doesn't seem to be an answer online. Note that my program doesn't contain threads. Here is my code:

ImageIcon poppetje1         = new ImageIcon("img/poppetje1.jpg");
JLabel    poppetje2         = new JLabel(poppetje1);

...

public void jump() {
    try {
        poppetje2.setBounds(poppetje2.getX(), (poppetje2.getY()-5), poppetje1.getIconWidth(), poppetje1.getIconHeight());
        Thread.sleep(100);
    } catch(InterruptedException e) {
        e.printStackTrace();
    }
}

...

public void keyPressed(KeyEvent e) {
    if(e.getKeyCode() == KeyEvent.VK_W) {
        for(int c = 0; c < 10; c++) {
            jump();
            repaint();
        }
    }
}

I hope this is enough of my code, if I should upload the complete code, please ask.

Thanks in advance for your time.

Answer 1

Does setBounds include a redraw/render step? If not, blocking within keyPressed is probably preventing the redraw from happening until the sleeps are all done and keyPressed returns.

Answer 2

Maybe you get an exception in this line of code poppetje2.setBounds(poppetje2.getX(), (poppetje2.getY()-5), poppetje1.getIconWidth(), poppetje1.getIconHeight()); and it's jumping directly on the catch statement.