strange directories

[jack]

I ran rkhunter this afternoon, and it asked me to check a few
directories, namely - 
/etc/.pwd.lock
/etc/.java
/dev/.static
/dev/.udev
/dev/.initramfs
/dev/.initramfs-tools

I'm trying to gather up info on these, since I'm not familiar with them.
/dev/.static is particularly disturbing, though, since it contains a
directory which essentially is a copy of all of /dev

If anyone has some insight about these, I'd appreciate knowing...