using java lambdas as groovy closure

using java lambdas from groovy

I have a scala method that takes java.util.function.Supplier as parameter.

class TestKit(system: ActorSystem) {
   def awaitCond(p: Supplier[Boolean]): Unit = tp.awaitCond(p.get)
}

syntactic sugar for Supplier functor would be () -> ... in java, but is not compiled in groovy.

def actorSystem = ActorSystem.create("actor-system")
def verifier = new TestKit(actorSystem)
verifier.awaitCond { -> return verifier.msgAvailable()}