hi,
I was encountering this problem and not having the tray icon with spark 2.5.8 in my gentoo linux, but now figure out, and please refer to the thread: http://www.igniterealtime.org/community/message/168330?tstart=0#168330
I see in the jira that I need to fire bug in this forum, so please review it. also I attach the fixed jniwrapper in that thread.