How to set Cyrillic in mnemonics for JMenu (mnemonics localization)?

Question

Java

How to set a Cyrillic letter as a mnemonic for a menu?
This is the code that works:

JMenu file = new JMenu("File");
file.setMnemonic('F');

And if the menu is in Russian, then no:

JMenu file = new JMenu("Файл");
file.setMnemonic('Ф');

At the same time, the mnemonic itself works out, i.e. when you start the program in the menu, the letter "F" is underlined, but the menu is not activated by alt + F.
At the same time, Russian mnemonics work for JMenuItem and other menu items.