code: public Issue updateIssue(Object projectIdOrPath, Integer issueIid, String title, String description, Boolean confidential, List<Integer> assigneeIds, 
              Integer milestoneId, String labels, StateEvent stateEvent, Date updatedAt, Date dueDate) throws GitLabApiException {
  
          if (issueIid == null) {
              throw new RuntimeException("issue IID cannot be null");
          }
  
          GitLabApiForm formData = new GitLabApiForm()
                  .withParam("title", title)
                  .withParam("description", description)
                  .withParam("confidential", confidential)
                  .withParam("assignee_ids", assigneeIds)
                  .withParam("milestone_id", milestoneId)
                  .withParam("labels", labels)
                  .withParam("state_event", stateEvent)
                  .withParam("updated_at", updatedAt)
                  .withParam("due_date", dueDate);
          Response response = put(Response.Status.OK, formData.asMap(), "projects", getProjectIdOrPath(projectIdOrPath), "issues", issueIid);
          return (response.readEntity(Issue.class));        
      }
docs: Updates an existing project issue. This call can also be used to mark an issue as closed.
  
  <pre><code>GitLab Endpoint: PUT /projects/:id/issues/:issue_iid</code></pre>
  
  @param projectIdOrPath the project in the form of an Integer(ID), String(path), or Project instance, required
  @param issueIid the issue IID to update, required
  @param title the title of an issue, optional
  @param description the description of an issue, optional
  @param confidential set the issue to be confidential, default is false, optional
  @param assigneeIds the IDs of the users to assign issue, optional
  @param milestoneId the ID of a milestone to assign issue, optional
  @param labels comma-separated label names for an issue, optional
  @param stateEvent the state event of an issue. Set close to close the issue and reopen to reopen it, optional
  @param updatedAt sets the updated date, requires admin or project owner rights, optional
  @param dueDate the due date, optional
  @return an instance of the updated Issue
  @throws GitLabApiException if any exception occurs