Java WatchService does not work in some folders

Question

I want to use Java 7 WatchService to track the /proc folder, but it doesn’t work (changes made to the folder are not reported), I tested other folders like /home/user/Desktop and /tmp and it works. What could be the reason? Is it because of permissions? /proc clearly owned by root, while the other folder belongs to the registered user. /tmp however also belongs to root, but it works. I use this basic implementation to test it.

My OS is Ubuntu 13.10 64bit. Oracle Java 1.7.0_51.

Answer 1

This is because / proc is not a normal file system and therefore does not support inotify:

https://unix.stackexchange.com/questions/90627/notify-of-changes-on-a-file-under-proc https://unix.stackexchange.com/questions/74713/how-frequently-is-the -proc-file-system-updated-on-linux? rq = 1