JDK-8072602 : Unpredictable timezone on Windows when OS's timezone is not found in tzmappings
  • Type: Bug
  • Component: core-libs
  • Sub-Component: java.util:i18n
  • Affected Version: 6u85,8u31,9
  • Priority: P3
  • Status: Closed
  • Resolution: Fixed
  • Submitted: 2015-02-05
  • Updated: 2016-06-13
  • Resolved: 2015-03-02
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6u105Fixed 7u91Fixed 8u60Fixed 9 b54Fixed
Related Reports
Duplicate :  
JDK-8067745 - Default TimeZone is GMT and user.timezone isn't set if user.timezone is invalid on Windows
Description
Java timezone("user.timezone") is unpredictable on Windows when the OS's 
timezone is not listed in the "lib\tzmappings" file. For example, 
"America/Bahia" is set wrongly as Java timezone in JDK-8060006's case, 
"Americas/Caracas" is set wrongly as Java timezone in JDK-7161087's case.  
These bugs show that which Java timezone is set in the no OS's timezone 
mapping case is unpredictable.

JDK-7161087 - Timezone is incorrect when OS timezone is set to Istanbul time
JDK-8060006 - No Russian time zones mapping for Windows

The unpredictable timezone(or unpredictable Java behavior) issue causes a 
huge confusion to not only users but also programmers and also prevents 
programmers from handling the no OS's timezone mapping case in their program.

So, please define the Java's predictable behavior for the no OS's timezone 
mapping case and change Java as taking the defined and predictable behavior. 
Setting Java timezone to "GMT" in the no OS's timezone mapping case might be 
a reasonable behavior.
Comments
When a Windows time zone ID (registry key) isn't found in tzmappings, the custom time zone ID based on the GMT offset of the Windows system, such as "GMT+09:00", is used.
18-02-2015