docs: public static ProtectedFunctionMapper getInstance() {
          ProtectedFunctionMapper funcMapper;
          if (System.getSecurityManager() != null) {
              funcMapper = (ProtectedFunctionMapper) AccessController.doPrivileged(
                              new PrivilegedAction() {
                                  @Override
                                  public Object run() {
                                      return new ProtectedFunctionMapper();
                                  }
                              });
          } else {
              funcMapper = new ProtectedFunctionMapper();
          }
          funcMapper.fnmap = new java.util.HashMap();
          return funcMapper;
      }