The Rootbeer GPU Compiler makes it easy to use Graphics Processing Units from
within Java.

Rootbeer is more advanced than CUDA or OpenCL Java Language Bindings. With
bindings the developer must serialize complex graphs of objects into arrays
of primitive types. With Rootbeer this is done automatically. Also with language
bindings, the developer must write the GPU kernel in CUDA or OpenCL. With
Rootbeer a static analysis of the Java Bytecode is done (using Soot) and CUDA
code is automatically generated.
https://github.com/pcpratts/rootbeer1