661             }
 662         }
 663 
 664         // Get the time zone for zoneID. But not fall back to
 665         // "GMT" here.
 666         tz = getTimeZone(zoneID, false);
 667 
 668         if (tz == null) {
 669             // If the given zone ID is unknown in Java, try to
 670             // get the GMT-offset-based time zone ID,
 671             // a.k.a. custom time zone ID (e.g., "GMT-08:00").
 672             String gmtOffsetID = getSystemGMTOffsetID();
 673             if (gmtOffsetID != null) {
 674                 zoneID = gmtOffsetID;
 675             }
 676             tz = getTimeZone(zoneID, true);
 677         }
 678         assert tz != null;
 679 
 680         final String id = zoneID;
 681         AccessController.doPrivileged(new PrivilegedAction<Void>() {
 682             @Override
 683                 public Void run() {
 684                     System.setProperty("user.timezone", id);
 685                     return null;
 686                 }
 687             });
 688 
 689         defaultTimeZone = tz;
 690         return tz;
 691     }
 692 
 693     /**
 694      * Sets the {@code TimeZone} that is returned by the {@code getDefault}
 695      * method. {@code zone} is cached. If {@code zone} is null, the cached
 696      * default {@code TimeZone} is cleared. This method doesn't change the value
 697      * of the {@code user.timezone} property.
 698      *
 699      * @param zone the new default {@code TimeZone}, or null
 700      * @throws SecurityException if the security manager's {@code checkPermission}
 701      *                           denies {@code PropertyPermission("user.timezone",

 661             }
 662         }
 663 
 664         // Get the time zone for zoneID. But not fall back to
 665         // "GMT" here.
 666         tz = getTimeZone(zoneID, false);
 667 
 668         if (tz == null) {
 669             // If the given zone ID is unknown in Java, try to
 670             // get the GMT-offset-based time zone ID,
 671             // a.k.a. custom time zone ID (e.g., "GMT-08:00").
 672             String gmtOffsetID = getSystemGMTOffsetID();
 673             if (gmtOffsetID != null) {
 674                 zoneID = gmtOffsetID;
 675             }
 676             tz = getTimeZone(zoneID, true);
 677         }
 678         assert tz != null;
 679 
 680         final String id = zoneID;
 681         AccessController.doPrivileged(new PrivilegedAction<>() {
 682             @Override
 683                 public Void run() {
 684                     System.setProperty("user.timezone", id);
 685                     return null;
 686                 }
 687             });
 688 
 689         defaultTimeZone = tz;
 690         return tz;
 691     }
 692 
 693     /**
 694      * Sets the {@code TimeZone} that is returned by the {@code getDefault}
 695      * method. {@code zone} is cached. If {@code zone} is null, the cached
 696      * default {@code TimeZone} is cleared. This method doesn't change the value
 697      * of the {@code user.timezone} property.
 698      *
 699      * @param zone the new default {@code TimeZone}, or null
 700      * @throws SecurityException if the security manager's {@code checkPermission}
 701      *                           denies {@code PropertyPermission("user.timezone",