Optimize java startup speed

I spent lot of time to optimize the startup speed of my Java app from 10 seconds down to 6 seconds in my 2012 Mac air. I changed to MacBook 13″, the startup time become <=3. That proves the hard disk speed is the key to optimize the startup time.

I am facing a new problem in Retina display: When I resize the window, the screen update is a little bit slow.