Question

I must be using @Autowired wrong, but I don’t get exactly how. This is a Spring 3.0 Portal MVC app.

The services themselves are not spring-based (they’re auto-generated). There is an impl written around the service providing some custom functionality — these classes are auto wired.

The problem I’m having is that the my autowired class appears to be treated internally as static. And therefore, this code isn’t threadsafe.

Controller class:

@Controller
@RequestMapping("VIEW")
@SessionAttributes(value={"shoppingCartCommonBean"})
public class ShoppingCartAndOrderScreenHandler     
{   
    @Autowired
    AbstractServiceImpl releaseOrderService;

    . . . 

    @ActionMapping(value = "SubmitOrder")
    public void submitOrder(Model model, PortletRequest request) {

        try {
            ReleaseOrderContract contract = new ReleaseOrderContract();

            /* Initialize contract values from request */

            releaseOrderService.setServiceRequest(contract);

            logger.debug("ReleaseOrderImpl Hash: " + 
                          releaseOrderService.hashCode());

            releaseOrderService.invoke();

         }
     . . . .
     }
 }

Where the autowiring is declared in the springconfig.xml as

<beans xmlns="http://www.springframework.org/schema/beans"  . . . >
    <context:component-scan 
        base-package="com.marchon.orderentry.shoppingcartandorder.requesthandler" />
    . . . .
    <bean class="com.marchon.orderentry.serviceimpls.ReleaseOrderServiceImpl"
          id="releaseOrderService" />
    . . . .
</beans>

I’ve seen some suspicious behavior under heavy load, where when multiple threads execute the same impl simultaneously, they don’t maintain consistent contracts (which is, yes, a non-static class variable in the service impl). And sure enough, when I print out the hashmap of the impl I get identical hashmaps — identical objects.

[ebContainer : 1] [ShoppingCartAndOrderScreenHandler . 208] DEBUG - ReleaseOrderImpl Hash: 1385321106
[ebContainer : 3] [ShoppingCartAndOrderScreenHandler . 208] DEBUG - ReleaseOrderImpl Hash: 1385321106
[ebContainer : 0] [ShoppingCartAndOrderScreenHandler . 208] DEBUG - ReleaseOrderImpl Hash: 1385321106

I would have thought that the auto-wiring would create copies of the bean for each instance of the controller class. But it’s not. What am I not understanding?

Answer 1

Spring beans are "singleton" scope by default. If you need individual instances, "prototype":

<bean class="com.marchon.orderentry.serviceimpls.ReleaseOrderServiceImpl"
      id="releaseOrderService"
      scope="prototype" />

That it’s auto-wired isn’t relevant.