Zabbix-Java-Gateway is a new JMX monitoring component first appeared in Zabbix release 2.0.
Unfortunately it is based on non-free evil-licensed implementation of JSON so it couldn't be shipped in Debian.
Zabbix developers are aware of problem but somehow they do not give it as much attention as it deserves.

Fortunately a free JSON alternative has been made available so finally Dmitry introduced zabbix-java-gateway to Debian.
Also starting with version 2.0.8 Zabbix packaging got support for ODBC monitoring so now Zabbix packages in Debian are better than ever.