/** {@inheritDoc} */
  @Override
  public void stop(BundleContext bundleContext) throws Exception {
    super.stop(bundleContext);

    focusManager = null;
    versionService = null;
    meetTools = null;
  }
  /** {@inheritDoc} */
  @Override
  public void start(BundleContext bundleContext) throws Exception {
    focusManager = ServiceUtils.getService(bundleContext, FocusManager.class);

    Assert.notNull(focusManager, "focusManager");

    versionService = ServiceUtils.getService(bundleContext, VersionService.class);

    Assert.notNull(versionService, "versionService");

    meetTools = focusManager.getOperationSet(OperationSetJitsiMeetTools.class);

    Assert.notNull(meetTools, "meetTools");

    super.start(bundleContext);
  }