On a long serving Java app running on Windows 10 and on JRE 8 the user base started reporting a performance issue in the last couple of months. (32 bit)
I have found out that there is a pattern when the app is left to go to another program then there is a lag upon return to the Java app.
It feels like the JRE goes into some sort of sleep mode when losing focus and then needs some time to pick up again. In task manager the corresponding line - Java (TM) Platform SE binary - show Power Usage - High or Very High at that moment. There is no Thread doing any business logic at that time so it is related to returning the focus.
Is anybody aware of such a situation?