So of the feedback at the BED-Con encouraged me to reconsider the original goals of jbj, which eventually let to an entirely now project called toehold.
Even though both project are entirely separate from each other (at least right now), they share a common goal: Allowing the integration of legacy PHP code into a Java-based project with the possibility of a step-by-step migration.
jbj attacks this problem with the bold goal of implementing a comparable PHP interpreter inside the Java-VM in combination with a Code-converter. Though there have been some improvements so far - as well as a great learning experience - jbj is not anyway near completion or even ready for production.
toehold approaches the problem in a much simpler far more pragmatic way. Instead of recreating everything from scratch it offers a set of tools to support a close interaction between the Java-VM and the PHP-interpreter. The first building block is a non-blocking FastCGI client based on akka and a corresponding plugin for the Play framework. With these two simple tools its already possible to integrate any kind of PHP-application into (or rather behind) a Play-application.
Of course this should be just the start, and there is some hope that all the work spend on jbj will not be wasted.