is there a way to save values through various starts of an app? I need to save some statistics (records of a game). In objective-c I used UserDefaults, what's it in Java? If possible I'd like to take a simple way (one line of code).
one line of code
No, that's not going to happen. But if you just have simple data and not much of it then you can use SharedPreferences
There is a good, basic example of using SharedPreferences
here in the docs
But if you are going to be storing a lot of data for a game then you probably want to implement an SQLite DB
See Storage Options for what will work best for you.