On mac, in Java, keyPressed event doesn't fire for certain keys

Question

This is a really weird issue, but I just have a simple keyListener added to a JPanel that prints on keyPressed and on keyReleased. Usually it works fine, but on certain keys

Answer 1

I ran into this issue recently, it is caused by the MacOS showing a context menu when you hold certain keys down (To allow you to chose alternative language characters) and the bug report page had a good solution that worked for me:

https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8167263

To disabled the character accent menu and enable auto-repeat, type the following at the command prompt:

defaults write -g ApplePressAndHoldEnabled -bool false

This can be reversed with the following:

defaults write -g ApplePressAndHoldEnabled -bool true

I just tried this on the mac console and my java application no longer has the key problem.

Answer 2

More troublesome keys were reported here

https://community.oracle.com/thread/4115318

It seems at this moment the best workaround is to avoid the use of

z, c, n, a, s, e, y, u, i, o

Answer 3

I fixed it by going into my system preferences -> keyboard and moving the key repeat slider all the way to the left to "Off".

Answer 4

It appears that this is a Java bug that arose after people upgraded to MacOS Sierra:

• Java Bug Database

• Reddit post

As a temporary workaround you might try using keys other than the standard WASD for controlling movement.