title: log4j2 PatternLayout Timestamp Format
body: <p>I want to specify logging timestamp in a particular format %d{YYYY-MM-dd HH:mm:ss.SSS}, but however I manipulate the pattern the timestamp is displayed as '2015-10-19 00:47:15,423'.</p>
  
  <p>Specifying %d{ISO8601} or %d{ABSOLUTE} are taking effect. I am wondering how the timestamp format is picked, when a custom pattern is specified.</p>
  
  <p>If I want to change the comma separator to period, is there a way to accomplish this?</p>