Someone already did that for us, it's called an IDE. I continue to be horrified by engineering re-write code that already exists.
Every one of these is a valuable optimization for some workflow somewhere. All of them reduce the compile/test cycle by seconds or minutes, speeding development. NONE of them are done by any IDE I'm aware of.
Seriously: write code to help you write code. If you aren't doing this, you probably aren't writing good code. And if you gave that answer in an interview, I for one wouldn't hire you.
That's why I'm always wondering why anyone would so much want to waste time with typing Java on VIM (even though I DO use Vim for other programming tasks) instead of just using an IDE specifically customized to make such development faster and easier.
I use Maven for all my Android builds.