Implementing Hot key combination (alt + ~) in Linux

Question

I am working on migrating features of an application in Windows OS to Linux OS. I got hot- keys to work but I want the specific combination "ALT + ~". So here is the code

event.isAltDown() && event.getCode() == KeyCode.BACK_QUOTE

But this combination clashes with the Linux in-built hotkey that displays the task manager instead of the Dialog box associated with my application. This dialog box displays if I give any other hot keys combinations like

event.isAltDown() && event.getCode() == KeyCode.J

I need some guidance to implement the ALT + ~ hot key without manually asking the users to turn off the hot key from Linux settings.

Thanks