docs: private static String getDefaultRealm(UserRegistry _userRegistry) {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.entry(tc, CLASS_NAME + "getDefaultRealm");
          }
          String realm = DEFAULT_REALM;
          if (_userRegistry != null) {
              realm = _userRegistry.getRealm();
          }
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) {
              SibTr.exit(tc, CLASS_NAME + "getDefaultRealm", realm);
          }
          return realm;
      }