The network is unreliable. 3G networking is slow. Using WiFi drains your battery. The NSA is spying on you. Different versions of HttpURLConnection have different bugs.
I'd like to talk OkHttp, a library I maintain, and how to use it to make your app's networking work even when conditions aren't ideal. I'll talk about how to configure caching to improve behavior and save resources. I'll talk about crypto. And I'll give advice on which libraries to use to make good networking easy.