Java Guy Introduction


Hi there!
Are there any other java guys out there ??


Me for one. Anything in particular you’d like to discuss?


Currently not. But maybe it’s a good idea if we introduce the topics that we working on.
And which java libs are we using or building.


Ok - recent work:

I just built a SHACL-based java <-> RDF ORM-like system:

  • reads a shacl shapes graph and generates java classes that map to the shapes
  • instantiates the classes for a given data graph
  • generates the RDF for a given set of java instances
    I called that ‘shacl2java’, currently as a maven module of a bigger project, but could be moved to its own project. It’s based on jena.

A few months ago I built a spring integration for RDF4J that mimicks spring-jdbc (including transactionality and result caching) Same thing: part of a bigger project, may make sense on its own.



  1. I am currently working on a simple ActivityPub C2S implementation with rdf4j.

  2. In another project I am trying to bring data (organizations) from different platforms into an RDF format and make it available in an RDF4J server. The goal is to later be able to search across platforms and find duplicates. And to use the data in other platforms, e.g. wordpress plugin.

  3. Then there is a model for ratings in the queue, there I’m trying to exchange with Will then probably flow into 2)

  4. We are currently discussing a semantic media wiki for some organizations where we need to find a categorization. Probably we will look at GND ( for this. This will then also somehow flow into 2).

  5. in the end 1-4 should work together somehow ,-)

1> is still closed source, but will be OSS until the end of 2021 (hopefully)
2-3> will be available with some common license

Is yours closed or open ?
btw. i’m a newby in semantic things and rdf :wink:


shacl2java is part of a major refactoring of the web of needs project - adding declarative authorization, it’s still a PR, so not so easy to find, but it’s all open source.

The spring/rdf4j one is closed for now, but I am tempted to publish it as open source especially if there is community interest


Web of Needs seems to have some similarities with ap. On a first very quick view?!


Some aspects really are similar, AFAICT. As for the differences, if I am not mistaken, ActivityPub is an API layer that you can implement on top of some social networking service, to make it interoperable with others that implement it. WoN prescribes not only the data exchange but also the internal data structures of the nodes. Also, the data model of WoN is more generic - you basically manage objects (“atoms”) and relationships (“connections”), which can probably be used in a similar way to AP.


ah, i understand, you are right! It depends on which end you start :wink:

From this point of view, i should take a closer look at your project.
How would you assess the progress or degree of completion and are several people working on the project?
What is your motivation for the project and how are you financing it?


You can try the demonstrator at Multiple people have been working on it, currently we are a team of 3. It is mostly funded by research grants, the motivation for starting it was to develop a federated cooperation system in which agents can publish their needs and their means of satisfying needs of others (you could call that supply and demand if you want).


Cool stuff! What ontologies / schemas are you using?

Unfortunately i don’t have enough time right now to look at this in more detail, but i would like to stay in contact with you. My friends from Vienna also immediately noticed the origin. I had not even noticed. Anyway, a very exciting project that coincides with some of our plans or more wishes.
Since I’m currently dealing with the mapping of SupplyChains: That doesn’t fit so badly with matchat either !??


Supply chains definitely are a good fit. We have done some work on combining WoN and ValueFlows, including an PDDL planner (using fastdownward) that can find combinations of supply and demand for production and transport scenarios.