title: Do I need to explicitly close connection?
body: <p>I'm holding one instance of <code>MongoClient</code> and <code>DB</code> in my application, and every time that I want to execute some operation I call <code>getCollection()</code>.<br>
  I'm wondering if I need to explicitly close the connection, just like <code>connection.close()</code> in JDBC.  </p>
  
  <p>To emphasize, I have only one <code>MongoClient</code> instance. My question is not about closing <code>MongoClient</code> but closing the connections I believe it opens when I'm calling <code>getCollection()</code>.</p>