code: @Override
      public void stop(BundleContext context) {
  
          if (systemConfiguration != null) {
              systemConfiguration.stop();
              systemConfiguration = null;
          }
  
          if (metaTypeRegistry != null) {
              metaTypeRegistry.stop(context);
              metaTypeRegistry = null;
          }
  
          if (null != caSupportTracker) {
              caSupportTracker.close();
              caSupportTracker = null;
          }
  
          if (null != locationTracker) {
              locationTracker.close();
              locationTracker = null;
          }
  
          if (null != variableRegistryTracker) {
              variableRegistryTracker.close();
              variableRegistryTracker = null;
          }
      }
docs: Called when bundle is stopped. Should undo what the start method did.
  
  A stopped bundle must not call any framework objects. There should be no
  active threads started by this bundle remaining when this method returns.
  
  @see org.osgi.framework.BundleActivator#stop(org.osgi.framework.BundleContext)