Why did you find lacking in java on Play? I've just started playing with it and aside from the template engine (which I don't count) I haven't found any part of the java support lacking vs the scala.
A minor demerit was getting SBT and Play Java to work correctly in IDEA was enough of a pain to make me wonder how much overhead that was going to incur in the long run.
If someone who has used Play Java in production on a large project can weigh in on whether these points are true or not in real production use, I'd love to hear it.
Going forward our new code is all in Scala. Not because we ran into issues with Play + Java, we just get fed up with Java's verbosity when dealing with futures and actors.