docs: private void setDefaultTimeZone() {
          String tzName = System.getProperty("use.time.zone");
          if ( tzName == null ) return;   // Use OS/user default.
          //
          // If tzName is bogus, not understood by the JRE,
          // 'getTimeZone' returns GMT.
          //
          TimeZone toSet = TimeZone.getTimeZone( tzName );
          //
          // Set default to whatever was returned.
          //
          TimeZone.setDefault( toSet );
      }