An ANTLRv3 compatible Java® 7 grammar (with some Java® 8 features - but yet not all) can be found within the download section. Actually this download contains two grammars: a parser grammar for producing ASTs (Abstract Syntax Tree) and a tree grammar that can be fed with the results produced by the parser grammar.

These grammars are also part of the JSourceObjectizer but they have been made available separately for all those who want to build their own parser for whatever reason. However, for using these grammars directly some knowledge is needed about grammars, parsers and ANTLRv3, of course, whereas for using the JSourceObjectizer it's enough just to have Java® skills.