code: public void updateDates(long dateLastModified, long dateExpires) {
  
          int pos = m_flexContextInfoList.size() - 1;
          if (pos < 0) {
              // ensure a valid position is used
              return;
          }
          (m_flexContextInfoList.get(pos)).updateDates(dateLastModified, dateExpires);
      }
docs: Updates the "last modified" date and the "expires" date
  for all resources read during this request with the given values.<p>
  
  The currently stored value for "last modified" is only updated with the new value if
  the new value is either larger (i.e. newer) then the stored value,
  or if the new value is less then zero, which indicates that the "last modified"
  optimization can not be used because the element is dynamic.<p>
  
  The stored "expires" value is only updated if the new value is smaller
  then the stored value.<p>
  
  @param dateLastModified the value to update the "last modified" date with
  @param dateExpires the value to update the "expires" date with