What to I need to do to on my server to communicate with an Android app?
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I am currently writing and Android app, and I need to do some stuff with a server. Actually I just don't know where to begin, since I don't know very much about server side.

My Android app will send Java objects and images to my server, so what do I need to write or use on my server ? Is it possible to write Java code instead of PHP on the server side ?

Could you please give me the steps to prepare my server ?