title: Send device to device notification using firebase android
body: <p>I know this is quite simple question for all you but I want some different. The scenario is :</p>
  
  <p>I am implementing chat application using <code>Firebase</code>. I have almost implemented it but i want to implement push notification for it same as <code>WhatsApp</code>. </p>
  
  <p>For that I have set up my project and other necessary thing for push notification to <code>Firebase</code> server and in my java code too. I am able to send notification from firebase server and successfully able to get notification from it to the device in which the app is installed.</p>
  
  <p><strong>Question:</strong></p>
  
  <p>So when we are chatting with each other, and someone send us message which needs to be displayed in notification manager, do I need to again call <code>MyFirebaseMessagingService</code> so I can get message which sender sent me from the application?</p>
  
  <p>Also do I need to set up a FCM server for cloud messaging to communicate with client app?</p>