eclipse debugging keys not working

I have no idea how I made the keys disappear in the first place, but what fixed it was to reset the debug perspective (You can do this from Window->Reset Perspective or right clicking on the Debug Perspective button from the top right panel and then choosing reset).

Afterward restart eclipse.

Hope this helps.

I just had the same exact issue. It turned out it was the F Lock key on my Microsoft keyboard. If you have a Microsoft keyboard with an F Lock key, I suggest pressing it to toggle the state and see if that resolves your issue.

I know this is late and already answered but I ran into the same issue debugging an android project. The accepted answer did not fix my problem even after many IDE restarts. My fix was to go into the Preferences and under General -> Keys. Then order list by key and look for F5-F8 "Debug Step Into, Over, Return and Run". I highlighted each one and clicked "Restore Command", then restarted Eclipse... this seemed to work for me.