title: Firebase + Android + Spring to create microservices
body: <p>Here is the idea:</p>
  
  <ul>
  <li><p>There is an android application that will consume services that I will create using Spring. However, this services should have some sort of security, so only people logged in on my android app can consume such services.</p></li>
  <li><p>On my android app, I will use Firebase to do the authentication, using email and password. So, there will be no need for me to configure any server to make this control. (Like Spring OAuth2)</p></li>
  </ul>
  
  <p>The question is, once the user is logged on my app and wants to consume some service, for example GET LIST of something, that I will provide on the Server using Spring, how can I check if the user is logged on the app, so I can grant access to that service? </p>