I did something stupid. I was screwing around with xmodmap a few weeks back, and gave up what I was trying to do. I find out later that Shift-J no longer does anything (I can't type capital "J").
xmodmap -pke shows the following for what appears to be the "J" key:
keycode 44 = j J j J
I want to restore normal behavior for Shift-J. Where do I start?