code: public Object addingService(ServiceReference reference)
      {
          HttpService httpService = (HttpService) context.getService(reference);
  
          this.properties = this.updateDictionaryConfig(this.properties, true);
          try {
              String alias = this.getAlias();
              String servicePid = this.properties.get(BundleConstants.SERVICE_PID);
              if (servlet == null)
              {
                  servlet = this.makeServlet(alias, this.properties);
                  if (servlet instanceof WebappServlet)
                      ((WebappServlet) servlet).init(context, servicePid, this.properties);
              }
              else
                  if (servlet instanceof WebappServlet)
                      ((WebappServlet) servlet).setProperties(properties);
              if (servicePid != null)   // Listen for configuration changes
                  serviceRegistration = context.registerService(ManagedService.class.getName(), new HttpConfigurator(context, servicePid), this.properties);
  
              httpService.registerServlet(alias, servlet, this.properties, httpContext);
          } catch (Exception e) {
              e.printStackTrace();
          }
  
          return httpService;
      }
docs: Http Service is up, add my servlets.