here is way of improving 3D by hardly reducing polygon count, very interresting tools …
Is this an ad?
nop sorry if it look such, I just see this tools while crawilng on the web and found that reducing 500000 to 1000 poly was awesome and can be usefull
EDIT:
also I really think this should be doable in java, algorithm doesnt seems to be that complex, I may at least try to do such tools later 
Looks very good - you can get a free trial version but you have to ask them for it :-\
Impressive results, most of the mesh simplification methods I’ve seen produce lousy models when dropping half as many polys. Would be really useful for automatically generating lower LOD meshes or for cross platform development.
Blenders, decimate option is basically the same thing, except…
The one thing that i can tell is different, Is that in Blender you have to re-do all the UV image co-ordinates after decimating.