I’ve been working with this project for some time.
Today grey strikes appeared through the folders of one project (PhoneStreamingActivity).
Why?
I was wiring up the jni component of my project and moving some files between packages when it happened.

From this website grey bars mean method is deprecated. Perhaps something in the folder is deprecated.
http://help.eclipse.org/indigo/index.jsp?topic=/org.eclipse.jdt.doc.user/reference/ref-icons.htm