Rendering artifacts for Qt and Java applications after running Ubuntu 15.10 (and others) for a long time?

Question

Java

Brief background of the problem:
After updating to Ubuntu 15.10, when I worked for a long time in IntellijIDEA, when I opened any Qt applications, instead of a normal window, I observed various artifacts: some parts of the window were not drawn, somewhere the inscriptions ran into each other, which did not allow using these applications. We managed to fix this behavior thanks to the answer found on the archlinux forum , namely due to the prescribed settings for Qt, as well as the transition from openjdk to oracle.
The second story, which seems to be related to the first one, is that when running and debugging applications (Java + Swing) for a long time, dialogs and windows in IntellijIDEA, as well as in debugged applications (written in NetBeans RCP) could become transparent , inaccessible, or just click through. Only restarting clients helps. This problem is also observed by my colleagues who use, for example, Fedora + KDE.
The bug is very unpleasant, because. our products running under *nix also make dialogs unclickable and redrawable from time to time. Browsing the bugtrackings of various manufacturers did not lead to anything, although I still hope that there will be a clear explanation for the appearance of this bug.
There is a working hypothesis why this is happening, but I lack the knowledge to bring it to its logical conclusion. The meaning is that if the x-server is configured incorrectly and if Qt and Java applications (each of which has its own toolkits) run for a long time at the same time, they begin to conflict, which leads to the appearance of artifacts.

Answer 1

There is a working hypothesis why this is happening, but I lack the knowledge to bring it to its logical conclusion.

Many people have this: https://www.linux.org.ru/forum/general/12077621
https://bugs.kde.org/show_bug.cgi?id=350976
https://bugs.launchpad.net/ubuntu/ +source/openjdk-... (follow the link you will find several "solutions" to the problem, like setting the environment variable QT_X11_NO_MITSHM to 1, etc.)
This is a problem in Java, it clogs and does not clean shmem. Google the phrase "Java Qt shmem". In your case, only updating the JRE / JDK will help. GTK+ applications don't tamper with shmem as often as Java or Qt, so the problem is rarely seen on popular GTK environments. However, the bug still exists.
File a bug report in your distribution's bugtracker (I understand that you're using Fedora) if it's not already running.