code: public Object getServiceObject(Exchange exchange, Object serviceObject) {
  
          JaxRsFactoryBeanCustomizer beanCustomizer = findBeanCustomizer(serviceObject.getClass());
          if (beanCustomizer != null) {
              final OperationResourceInfo ori = exchange.get(OperationResourceInfo.class);
              final ClassResourceInfo cri = ori.getClassResourceInfo();
  
              Object o = beanCustomizer.beforeServiceInvoke(serviceObject,
                                                            cri.isSingleton(),
                                                            getBeanCustomizerContext(beanCustomizer));
              if (o == serviceObject && !beanCustomizer.getClass().getName().equalsIgnoreCase("com.ibm.ws.jaxrs20.ejb.JaxRsFactoryBeanEJBCustomizer")) {
                  //call postConstruct method if it has not been repleaced with EJB/CDI for per-request resources
                  Method postConstructMethod = ResourceUtils.findPostConstructMethod(o.getClass());
                  InjectionUtils.invokeLifeCycleMethod(o, postConstructMethod);
  
              }
              return o;
          } else {
              //if bean customizer is null, means it is a pojo, we need to call postConstruct here
              Method postConstructMethod = ResourceUtils.findPostConstructMethod(serviceObject.getClass());
              InjectionUtils.invokeLifeCycleMethod(serviceObject, postConstructMethod);
              return serviceObject;
          }
      }
docs: call by LibertyJaxRsInvoker
  
  @param exchange
  @param serviceObject
  @return