Recently, our Java application was a bit slower than usual, we just ignored it, because we use cloud DB which is a bit slow sometimes.
I used to navigate to other windows by pressing (alt+tab) in the windows machine. One day I found many JDialog boxes are opened. When we click it, nothing happens and it is also not shown. Again, when I press alt+tab, it is still here.
If I kill the application all the dialog boxes vanish. Since our codebase is huge with 5000+ Java classes, we don't know how to find this dialog box.
you can create a heap dump using jmap (jmap -dump:file=filename PID). after that you can see in the dump which of the JDialog remained in memory using the visual vm