code: public static Calendar parseDateFormat(String s, DateFormat dateFormat,
  										   TimeZone tz) {
  		ParsePosition pp = new ParsePosition(0);
  		Calendar ret = parseDateFormat(s, dateFormat, tz, pp);
  		if (pp.getIndex() != s.length()) {
  			// Didn't consume entire string - not good
  			return null;
  		}
  		return ret;
  	}
docs: Parses a string using {@link SimpleDateFormat} and a given pattern. The
  entire string must match the pattern specified.
  
  @param s       string to be parsed
  @param dateFormat Date format
  @param tz      time zone in which to interpret string. Defaults to the Java
  default time zone
  @return a Calendar initialized with the parsed value, or null if parsing
  failed. If returned, the Calendar is configured to the UTC time zone.