Are there any other Java libraries for bonjour/zeroconf apart from JMDNS?
Try avahi4j (https://code.google.com/archive/p/avahi4j/). But the project is archived and there is no active development from 2009.
I've been working on a simple, pure Java implementation of mDNS Service Discovery. At the moment only synchronous browsing is supported, but I plan to add an asynchronous listener in the next release. It's free software and available on GitHub at https://github.com/fflewddur/hola.
The only requirements are Java 8 and having the slf4j-api available in your class path.
I've found more easy to create my own implementation (after experience with WS-Discovery and Bonjour for cross-platform cases) https://github.com/4ntoine/ServiceDiscovery-java. It has both Java and iOS impl for both client and server side.
I'm also curious to find the best cross-platform DNS-SD (Zeroconf, Bonjour, DNS self discovery) library exists out there.
It does sound like Apple's DNS-SD dnssd.jar is the "official" Java library that requires native library support on Windows, Linux, etc, but works out of the box on Mac OSX.
There are other pure Java DNS-SD implementations, but it's unclear if any of them offer a library that is as easy to use or fully tested as DNS-SD (some of the projects appear to be abandoned for 2 years).
Try at:
DNS-SD
-- The same Java DNS-SD APIs are also available in Bonjour for Windows, Bonjour for Linux, Solaris, *BSD, etc., enabling Java software to make use of Zeroconf's DNS Service Discovery across a wide range of platforms, not just on Mac OS X ......
Waiter seems to be a pure Java library for DNS-SD. It's available here:
http://code.google.com/p/waiter/