More than hundreds, even. It also allows you to delegate rendering computations - which are very expensive - off of the CPU (which isn't really designed for it) and onto the GPU (which is). Not only does this improve your performance, but you're not wasting a ton of CPU memory with rendering buffers/textures, and you have many more options with how to perform your rendering, since Java2D is extremely limited.
Trust me on this - I started making a game engine based on Java2D before I found LWJGL, and the performance difference is AMAZING.
Oh, and I found it odd you were asking about Java2D on a OpenGL-centric forum. There really isn't much of an overlap.