Java BufferedImage how to know if a pixel is transparent

BufferedImage img = ....

public boolean isTransparent( int x, int y ) {
  int pixel = img.getRGB(x,y);
  if( (pixel>>24) == 0x00 ) {
      return true;
  }
  return false;
}

Of course img has to be in the correct format TYPE_4BYTE_ABGR or some format that supports alpha channels else if will always be opaque (ie 0xff).