I'm discovering activities (along with KDE 4, which in version 4.6 seems like an amazing job).

Anyway, activities seem like a good idea, specially when (some when in the future, hopefully) apps will be "hibernated" when not used.

Until then, app restart is a fair solution. But I'm running a java app (Oracle Jdeveloper) which is not affected by activity stop command. It's started as a shell script which (among many other things) executes java command.

Any ideas how to make it stoppable?

Thanks!

Have you checked to see if this Java application complies with the X Session Manager protocol? If it is not compliant, then it may not respond to Plasma's request to close it.