title: Java time since the epoch
body: <p>In Java, how can I print out the time since the epoch given in seconds and nanoseconds in the following format :</p>
  
  <pre><code>java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
  </code></pre>
  
  <p>My input is:</p>
  
  <pre><code>long mnSeconds;
  long mnNanoseconds;
  </code></pre>
  
  <p>Where the total of the two is the elapsed time since the epoch <code>1970-01-01 00:00:00.0</code>.</p>