Sets wrong filetype for jar files

[m-bernard]

When I use this plugin, it causes Vim to treat jar files as tar files.

:verbose set ft?
filetype=tar
Last set from /usr/share/vim/vim74/autoload/zip.vim

But if I remove this plugin, Vim correctly opens jar files.

[bogado]

Is this happening on the same use cases listed in this comment? I feel like this is the same issue in disguise. Unfortunately I don't know yet how to fix it.