After closing Firefox remains in the processes, how to win?

Question

Mozilla Firefox

After closing Firefox, it remains in processes
running multi-user mode.
The difficulty arises that firefox does not restart without killing, I noticed a hang-up dependency with the java process, but java is needed for work.
Has anyone solved such a problem? There is only 1 addon - and there were no problems with it before.
Mazila is old - it is not possible to update.