github https://github.com/nviennot/jd-core-java
JD-Core-java is a thin-wrapper for the Java Decompiler.
This is hack around the IntelliJ IDE plugin. It fakes the interfaces of the IDE, and provides access to JD-Core.
Since the Author of JD-Core is not willing to provide a library, and we all want to batch decompilation, this is pretty much our only option.
I hope this will motivate the author to release a proper library.