Comment 11 for bug 309778

I haven't looked at the jar spec lately, but it should be a safe assumption that all jar files have a META-INF folder. I don't think you can assume a fixed location for it though.

Also, this report seems to be focused on so-called 'executable' jar files, which have the distinction of defining a Main-Class property in the META-INF/MANIFEST.MF file.

For reference, here http://java.sun.com/docs/books/tutorial/deployment/jar/index.html is a general overview; I'm sure there's a more technical spec available too.