code: public CMAEditorInterface update(CMAEditorInterface editor) {
      final String spaceId = getSpaceIdOrThrow(editor, "editor");
      if (editor.getSystem().getContentType() == null) {
        throw new IllegalArgumentException("ContentType of editor interface may not be null!");
      }
      if (editor.getSystem().getContentType().getId() == null) {
        throw new IllegalArgumentException("Id of ContentType of editor interface may not be null!");
      }
      final String contentTypeId = editor.getSystem().getContentType().getId();
      final String environmentId = editor.getEnvironmentId();
      final Integer version = getVersionOrThrow(editor, "update");
  
      CMASystem old = editor.getSystem();
      editor.setSystem(null);
  
      try {
        return service.update(spaceId, environmentId, contentTypeId, editor, version).blockingFirst();
      } finally {
        editor.setSystem(old);
      }
    }
docs: Update an editor interface.
  
  @param editor the editor interface to be updated on Contentful.
  @return the updated editor interface.
  @throws IllegalArgumentException if editors spaceId is null.
  @throws IllegalArgumentException if editors contentType is null.
  @throws IllegalArgumentException if editors contentTypeId is null.
  @throws IllegalArgumentException if editors version is not set.