Facebook is known for having fairly bad code standards in their mobile apps. It's mostly a product of overengineering and feature creep.

This is a good blog post about it: http://www.darkcoding.net/software/facebooks-code-quality-pr...

And Facebook's own blog post about their Dalvik hacks and how clever they are, which speaks volumes of their development culture: https://www.facebook.com/notes/facebook-engineering/under-th...