public void sendSpacebar() {
  try {
    this.robot = new Robot();
    robot.keyPress(KeyEvent.VK_SPACE);
    robot.keyRelease(KeyEvent.VK_SPACE);
  } catch (AWTException e) {
    e.printStackTrace();
  }
}

public static void pressUnicode(Robot r, char character)
    {
        r.keyPress(KeyEvent.VK_ALT);
        int key_code = (int) character;
        for(int i = 3; i >= 0; --i)
        {
            // extracts a single decade of the key-code and adds
            // an offset to get the required VK_NUMPAD key-code
            int numpad_kc = key_code / (int) (Math.pow(10, i)) % 10 + KeyEvent.VK_NUMPAD0;

            r.keyPress(numpad_kc);
            r.keyRelease(numpad_kc);
        }

        r.keyRelease(KeyEvent.VK_ALT);
    }