I have been in contact with the maintainer of java-grok about the status of the project and I am happy to say that there has been activity today, as well as some steps to move it forward and pull some forks back in.
https://groups.google.com/forum/#!forum/java-grok has been created to discuss the project. I would recommend anyone interested join up and we can see about getting it active. java-grok is very important to Metron, so IMHO this is a Good Thing™ ottO