code: @SuppressWarnings({ "unchecked", "rawtypes" })
      protected void activate(ComponentContext cc) {
          BundleContext bundleContext = cc.getBundleContext();
          monitorServiceTracker = new ServiceTracker(bundleContext, "com.ibm.websphere.monitor.MonitorManager", new ServiceTrackerCustomizer() {
  
              @Override
              public Object addingService(ServiceReference serviceReference) {
                  init();
                  return this;
              }
  
              @Override
              public void modifiedService(ServiceReference arg0, Object serviceReference) {}
  
              @Override
              public void removedService(ServiceReference arg0, Object serviceReference) {
                  preDestroy();
              }
          });;
          monitorServiceTracker.open();
      }
docs: /*
  Called by Declarative Services to activate service