As Java 6 is in end of life status for a long time, i think it is safe to drop Java 6 support in Spark completely. I think it is sufficient to have Spark 2.6.3 to still support it, but all newer version should work with Java 7 and don't have hooks to Java 6 anymore. Support for Java 6 is creating issues like described in the forum thread linked to this ticket. If users have Java 6 on their system (they need it for some reason), then Spark will use that older Java no matter the fact that it has Java 7 bundled. So old java bugs are crawling back (focus stealing, tray icon distortion and other issues). We then get bug reports about such issues which can't be fixed any way other than dropping Java 6 hooks.
Walter, is it fine with you and your developers to mark this for 2.7.0 version? Of course i don't know how much work it involves. Maybe some other contributor will do this.
The online installer (install4j) is also set to search for java 5 or 6 so one can't even install Spark online without having old java installed on the system http://community.igniterealtime.org/message/234758#234758
So far, together with Daryl we were able to change Bamboo plan to use java 1.7 as minimum version and 1.8 as max. This had two effects. New online installer is installing fine if Java 5-6 is not present on the system and Java 7 is installed. A side effect is that it won't install if you have only java 5-6 on the system, but i think it is ok. Spark 2.7.0 will drop old java support, and 2.6.3 still will work with Java 6. Also you can't even run Spark installed with new installer, if you have only java 6 on the system. After the final release there can be reports, that Spark doesn't work, but i think this should be minimal and such users can use full installer which includes java 7. Or use Spark 2.6.3..
Another more important achievement (need to test it more next week to close this ticket for good) - now if you have java 6 on the system and install Spark 2.7.0 with java 7 bundled it WON'T use that older java 6. So many bugs related to Java 6 will disappear (focus stealing, crappy system tray icon, etc.).
I've tested today at work on a machine with Java 18.104.22.168 installed. Well, i wasn't able to reproduce the focus stealing bug before updating to Spark 642 build. But after the updating at least the system tray icon wasn't distorted anymore.