docs: public static void setDefault(DateTimeZone zone) throws SecurityException {
          SecurityManager sm = System.getSecurityManager();
          if (sm != null) {
              sm.checkPermission(new JodaTimePermission("DateTimeZone.setDefault"));
          }
          if (zone == null) {
              throw new IllegalArgumentException("The datetime zone must not be null");
          }
          cDefault.set(zone);
      }