IV18033: DIFFERENCE OF 4 SECONDS IN DATE->STRING->DATE CONVERSION USING SIMPLEDATEFORMAT CLASS WITH ASIA/RIYADH89(/88/87) TIMEZONES

APAR status

• Closed as Permanent restriction.

Error description

• Error Message: When a date object is formatted using
  SimpleDateFormat with TimeZone set to Riyadh89/88/87 and  parse
  back to the Date object, there is a 4 seconds difference when
  the format string contains TimeZone pattern(i.e., Z or zzzz).
  .
  Stack Trace: N/A
  .
  

Local fix

• 1. Use Asia/Riyadh TimeZone which is currently active.
  .
  2. If the Asia/Riyadh87(88/89) needs to be used, avoid using
  format strings containing TimeZone specifiers in format string
  of DateFormat object with Asia/Riyadh87(88/89) (using Z or zzzz
  in the format String).
  

Problem summary

• The problem was caused as Riyadh 87-89 time zones  do not follow
  the common time zone standards - RFC822 time zone or Generalized
  Time zone standards where as JDK follows common time zone
  standards.
  
  While using SimpleDateFormat class to convert a date to a
  string, only the seconds precision in the Time zone offset is
  considered. This is well documented in the SimpleDateFormat
  class API as it follows RFC822 timezone or Generalized Time zone
  standards. All the standard locales are standardized their time
  zone offset to 15, 30, 45 or 00 minutes. Hence "Asia/Riyadh"
  time zone is standardized to 03:00.
  
  IBM JDK retains Riyadh87-89 time zones for compatibility purpose
  as any application which continues to use Riyadh87-89 time zones
  can break if they are removed.
  

Problem conclusion

• When you convert a Date to string using SimpleDateFormat format
  with Riyadh87-89 time zone, the JDK will use Riyadh87-89 time
  zone offset for the conversion. Here, you are losing 4 seconds
  offset as seconds precision offset are not preserved in the
  string format. When the string is parsed back to Date, it uses
  the time zone offset from the string and hence, every time you
  do a Date -> String -> Date conversion, you will gain 4 seconds
  which explains why you are seeing the 4 seconds difference every
  time.
  
  In order to fix this issue, either the seconds value in
  Riyadh87-89 time zone offset has to be ignored while doing the
  formatting from Date to String or JDK has to add the seconds
  precision to string format.
  
  If the seconds value from Riyadh87-89 time zone offset is
  ignored, JDK will provide incorrect timestamp in the string
  format. In order to add the seconds precision to string format,
  JDK has to deviate from the common standards (RFC822 timezone
  and Generalized Time zone). Hence JDK decided not to fix this
  issue and considered this as a perminent restriction.
  

Temporary fix

Comments

APAR Information

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Fix information

Applicable component levels