I've recently been quite interested in Graph languages, not for Graph Databases, but for representing information, in code that is essentially "things" and "relationships". For example, one perspective on Organizations is that they are simply representable as people, systems and the information that flows between them. Those three building blocks are, in theory, enough to describe anything from a small business to a government, if you have an appropriate way to describe all the information, ensure the connections make sense, and report on it. If you further layer on the idea of systems of systems, you have the ability to describe different levels of government, business units, departments and so on. Public and private flows of information allow models that accurately represent the fact that no organization is fully meshed: the systems only expose certain information.
The reporting on it is quite interesting, and led to be becoming interested in DOT as a way to describe reports resulting from queries. I didn't find a small, embeddable Java library that enabled me to read and write DOT files, so I ended up writing DOT4J.
The writing of DOT files, is trivial. The reading however, ended up requiring a lexer-parser since DOT is, essentially a programming language of its own. The grammar came from ANTLR, of course.
DOT4J is here. The Github page has the Maven co-ordinates for published binaries.