So this is the global logger used from Scala:

https://github.com/playframework/playframework/blob/master/framework/src/play/src/main/scala/play/api/Play.scala#L35

The Scala logger methods uses by-name parameters, so not so good from Java.

I don't see a global internal logger for Java code. Shall I add one somewhere? Is there already a place for this kind of thing?