code: public void start() {
          if (classResolverRegistration != null) {
              throw new IllegalStateException("Service is already registered");
          }
          Dictionary<String, String> properties = new Hashtable<String, String>();
          properties.put(Constants.APPLICATION_NAME, applicationName);
          try {
              classResolverRegistration
                      = paxWicketBundleContext.registerService(IClassResolver.class, this, properties);
  
          } catch (NullPointerException e) {
              LOGGER.error("nullpointer while trying to register >{}< using {} with >{}< bundlecontext are >{}<", IClassResolver.class, this, properties, paxWicketBundleContext, e);
              throw e;
          }
          {
          }
  
      }
docs: <p>start.</p>