title: how to write a query get Firestore current server time using firebase java admin sdk
body: <p>I want to write a query to get a list of document which was saved in the past 24 hours. When the document was created, I add a "last updated" value using <code>FieldValue.serverTimestamp()</code>. Now my query would be like:</p>
  
  <pre><code>Date pastDay = (getFireStoreServerTime) - (24hours)
  Query query = collectionRef.orderBy("lastUpdated", Query.Direction.DESCENDING).where("last updated" &gt; pastDay);
  </code></pre>
  
  <p>However, I wasn't able to find the API in java admin SDK to get the server time. Is this supported in Firebase Admin SDK for Cloud FireStore?</p>