(Photo: Leaf on my car by exfordy)

The ATG Date Tag Converter is buggy because Java’s DateFormat is inherently unsafe for multithreaded use.  This is documented in ATG PR #123210 DateTagConverter.convertObjectToString() method is not thread safe.

You run into this problem whenever you do something like this.

<dsp:valueof param=”creationDate” converter=”date” date=”M/dd/yyyy”/>

Unfortunately there is no work around.  If using the Date Tag Converter is not causing problems for you, i.e you don’t see a stack trace like below, then you can ignore this bug.

2009-04-17 00:19:08,220 ERROR [nucleusNamespace.atg.dynamo.servlet.dafpipeline.DynamoServlet] java.lang.ArrayIndexOutOfBoundsException: 502
  at sun.util.calendar.BaseCalendar.getCalendarDateFromFixedDate(BaseCalendar.java:436)
  at java.util.GregorianCalendar.computeFields(GregorianCalendar.java:2081)
  at java.util.GregorianCalendar.computeFields(GregorianCalendar.java:1996)
  at java.util.Calendar.setTimeInMillis(Calendar.java:1071)
  at java.util.Calendar.setTime(Calendar.java:1037)
  at java.text.SimpleDateFormat.format(SimpleDateFormat.java:785)
  at java.text.SimpleDateFormat.format(SimpleDateFormat.java:778)
  at java.text.DateFormat.format(DateFormat.java:314)
  at atg.droplet.DateTagConverter.convertObjectToString(DateTagConverter.java:176)

But if you do see a bug like this then you might need to create a custom droplet to format the date.  The droplet should only use DateFormat instances that are not static.  I usually make my DateFormat instances local.