Android expert, answer few questions [paid project]

Hi... I need someone who is "very" experienced in android & app development. This quick project consists of two requirements: 1- Answer my questions regarding signing the APK file... I don't understand the process very well, so I I have few things that I need to ask about.. if you're familiar with digital signing of an APK, as well as things like: [login to view URL] / [login to view URL] / [login to view URL] ..etc.. then you'll probably be able to answer my questions :) don't worry, I don't have hundreds of questions... only several questions about the process to help me understand this signing thing! 2- I will give you 2 versions of sources codes (very simple code, nothing complicated here)... Both are built/compiling successfully (on my environment). However one of them is signed during the process, while the other sources are not signed! (on the same machine & same environment...etc) As i said, both are built successfully. I need you to have a look at these two sources, and just "tell" me what is causing the second sources not to be signed at the end of the process! You won't need to write/modify any code (unless it's something very simple)... All what you need is to "discover" why source 1 is built successfully AND signed. while source 2 is built successfully but NOT signed. Quick project... hopefully will lead to something bigger in future :) Thanks, Mary .