I'm using firestore in my android project, everything working fine.But Yesterday an issue occurred on getting timestamp value from document snapshot.

if (documentChange.getType() == DocumentChange.Type.ADDED) { 
  Map stringObjectMap = documentChange.getDocument().getData(); 
  Date date = (Date) stringObjectMap.get("timestamp"); }

This is one of my Collection Document.

 id : "25",
 message : "This is my message",
 timestamp : December 11, 2017 at 10:39:12 PM UTC+5, \\This is Firebase FieldValue.serverTimestamp()
 username : "Temp"

I get everything from the document except for timestamp.