Procuder-consumer example in Java and Clojure

I want to implement a very simply consumer-producer app. One consumer consuming from a large number of producers. I would like to see how much throughput is possible in accordance with the number of producers.

The first implementation is in Java
The Clojure version

The Java one is really struggling under 100 producers. I haven't done any tuning on the ExecutorService, though, but in the Clojure version I didn't even need to. The latter is distributing the load extremely evenly and reaches a much higher throughput than the Java version.