title: What is android.jar ? What does it include?
body: <p>I am a noob with android development. What is android.jar? I am referring to <a href="https://developer.android.com/guide/platform/?nav=true" rel="noreferrer">https://developer.android.com/guide/platform/?nav=true</a> and trying to understand which layer it fits into. I heard conflicting opinions and am now really confused, considering my limited knowledge in Android. Thanks!</p>