Programmatically clicking a GUI button in Java Swing
Have you tried using doClick()?
If doClick() is not what you want, you can move the mouse really to the button and press it:
public void click(AbstractButton button, int millis) throws AWTException
{
Point p = button.getLocationOnScreen();
Robot r = new Robot();
r.mouseMove(p.x + button.getWidth() / 2, p.y + button.getHeight() / 2);
r.mousePress(InputEvent.BUTTON1_MASK);
try { Thread.sleep(millis); } catch (Exception e) {}
r.mouseRelease(InputEvent.BUTTON1_MASK);
}