Nsq-j is a new open source java client, written from scratch, with very few dependencies.
At Sprout Social we have been using it in production for billions of messages for over a year.
We had trouble debugging reconnection issues with the Trendrr (netty) based clients, so we wrote nsq-j to make sure messages keep flowing after network problems.
It uses synchronous io with helper methods to batch publish. Performance should be slightly better than the Trendrr clients, and you have the option to publish synchronously and wait for OK from nsqd without using callbacks.
We love nsq and are committed to maintaining this, so please file issues or chat here if you try it and run into any problems at all.
Thanks --
Rob Seed
Sprout Social