[Bug classpath/27362] New: Call to java.util.Calendar#clear() may discard java.util.Calendar#add() change

[kiyun dot roe at active-endpoints dot com]

A call to java.util.Calendar#clear() forces the Calendar object to recalculate
the time from the Calendar fields. However, java.util.Calendar#add() does not
always record the change to the field (recording just the effect on the
millis). So, calling clear() after add() may discard a change that was
introduced by add().

In the test case below, the calculated yesterdayStart is the same as
todayStart, because the effect of calendar.add(Calendar.DATE, -1) islost.

   public void testPreviousDate) throws Exception
   {
      Calendar calendar = Calendar.getInstance();
      Date now = new Date();

      // Calculate the start of today.
      calendar.setTime(now);
      calendar.clear(Calendar.HOUR);
      calendar.clear(Calendar.MINUTE);
      calendar.clear(Calendar.SECOND);
      calendar.clear(Calendar.MILLISECOND);

      Date todayStart = calendar.getTime();

      // Calculate the start of yesterday.
      calendar.setTime(now);
      calendar.add(Calendar.DATE, -1); // this change is lost
      calendar.clear(Calendar.HOUR);
      calendar.clear(Calendar.MINUTE);
      calendar.clear(Calendar.SECOND);
      calendar.clear(Calendar.MILLISECOND);

      Date yesterdayStart = calendar.getTime();

      assertTrue(yesterdayStart.before(todayStart));
   }


-- 
           Summary: Call to java.util.Calendar#clear() may discard
                    java.util.Calendar#add() change
           Product: classpath
           Version: 0.90
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: classpath
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kiyun dot roe at active-endpoints dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27362