title: calendar.gettimeinmillis vs system.currenttimemillis
body: <p>What is the difference?</p>
  
  <pre><code>cal.add(Calendar.DAY_OF_MONTH, -5);
  
  List&lt;UsageStats&gt; stats = mUsageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_BEST,cal.getTimeInMillis(), System.currentTimeMillis());
  </code></pre>