Kevin gave you a good list of what you really need to do first to improve the performance of the code. However I would just throw out the code and implement the effect on higher level so that Java can utilize native code and GPU.
Based on the screenshot it looks like the effect you are looking for is radial blur with rotation. These can be implemented by first rendering the scene to an offscreen image instead of directly to the screen and then repeatedly rendering the image to the screen with scaling and rotation. These are operations that Java can accelerate on the GPU automatically and you might get even better performance by creating the offscreen image as VolatileImage. Make sure you are using bilinear filtering for better quality:
In pseudo-code the algorithm would look something like:
render scene to offscreen_image
for i in 1 to N
scale = any function that returns 1 for the first image and approaches zero when i grows.
rotation = i * constant
render offscreen_image to screen with scale and rotation
When rendering the offscreen_image to the screen, you also probably want to fade it to background color a little. In Java you can do this with AlphaComposite.
This should be enough to make your effect fast enough. However there is still room for improvement.
The rendering time of the implementation above is proportional to N. In some cases, mainly if your frame rate is constant, you can further accelerate the rendering by keeping the previous rendering result in the offscreen image and rendering only one copy of the offscreen image. This makes the effect very fast, but the dependency of previous rendering results might be undesirable. This also limits the shape of the scaling and rotation functions. The pseudo-code for that would be:
render scene on top of offscreen_image_1 without clearing
scale = constant_1
rotation = constant_2
render offscreen_image_1 to offscreen_image_2 with scale and rotation
render offscreen_image_2 to screen
swap offscreen_image_1 and offscreen_image_2
Scale and rotation constants can still vary based on time / framecounter in this version.
You might have seen this effect in action in some music player visualization (Winamp, Media Player etc.). Here is an example video: https://www.youtube.com/watch?v=jasdVfbAFVw#t=237s.