code: @Override
      public String checkPassword(String userSecurityName, @Sensitive String password) throws RegistryException {
          if (userSecurityName == null) {
              throw new IllegalArgumentException("userSecurityName is null");
          }
          if (userSecurityName.isEmpty()) {
              throw new IllegalArgumentException("userSecurityName is an empty String");
          }
          if (password == null) {
              throw new IllegalArgumentException("password is null");
          }
          if (password.isEmpty()) {
              throw new IllegalArgumentException("password is an empty String");
          }
          if (this.user.equals(userSecurityName) && this.password.checkPassword(password)) {
              return user;
          } else {
              return null;
          }
      }
docs: {@inheritDoc}