code: public User getUser(int userId) throws GitLabApiException {
          GitLabApiForm formData = new GitLabApiForm().withParam("with_custom_attributes", customAttributesEnabled);
          Response response = get(Response.Status.OK, formData.asMap(), "users", userId);
          return (response.readEntity(User.class));
      }
docs: Get a single user.
  
  <pre><code>GitLab Endpoint: GET /users/:id</code></pre>
  
  @param userId the ID of the user to get
  @return the User instance for the specified user ID
  @throws GitLabApiException if any exception occurs