Develop Reference

How to use #Resource annotation in servlet (or in any other Java class)?

I am experimenting with Java Dependency Injection. Many questions here on SO talk about jndi resources being wired. But I think, a java class can be wired using #Resource annotation. I have a simple servlet in which I have two properties to be wired using CDI. I am using Tomcat6, Servlet 2.5, and Weld configuration.
The servlet code:
#Inject
private HikariConnectionProperties hikariConnectionProperties;
#Resource(name = "connectionProvider")
private IConnectionProvider connectionProvider;
However I get the code compiled, deployed. But, when there is a request for the corresponding servlet I get javax.naming.NameNotFoundException: Name connectionProvider is not bound in this Context.
But, I have #Named annotation for the ConnectionProvider class. The same configuration works with #Inject for both the fields.
So, my first question is how can I fix this issue? And is there any way that I can specify scope for a particular injection(using only annotations of JSR) without using Spring's #Scope? Any example is a great help as I am a newbie to CDI.

#Resource only works in Tomcat when you set up a resource in your container. Here's a reference for your own sake: http://tomcat.apache.org/tomcat-6.0-doc/jndi-resources-howto.html
It expects that you're binding a JNDI entry called "connectionProvider" in Tomcat. CDI does not bind elements to JNDI, it has its own internal mapping of objects to scopes. #Inject works here as you likely have not setup a resource for this class in your resource configuration.

Autowired Dependency Injection with Spring Security

I have a spring webapp with annotation driven configuration.
All Controllers, Repositories are autowired.
When integrating Spring Security I defined a separate security-app.xml. I created a Service called LoginUserService which implements UserDetailsService. Now the method loadUserByUsername() method of this class gets invoked for authentication.
This class has an autowired dependency for UserRepository. Now this autowired dependency turns out to be null. To fix this I enable annotation driven configuration and add the package name for the repository class in component scan configuration.
This solution is also discussed here
spring security with custom user details
But now the problem is that the UserRepository has an EntityManager field with #PersistenceContext annotation. For the spring security configuration it is able to locate the UserRepository but not able to locate the entity manager. Should I create a new EntityManagerFactory here? I guess that will create two persistence units in my application?
How can I inject an autowired dependency to UserRepository created with the original servlet xml?
Update
This is briefly discussed here:
https://stackoverflow.com/a/7078395/161628
But I guess a canonical detailed answer will be more useful to me.
Update
How about using ApplicationContext to get the UserRepository at runtime?
if (userRepository == null) {
userRepository = ApplicationContextProvider.getApplicatonContext().getBean(UserRepository.class);
}
Why is Spring's ApplicationContext.getBean considered bad?

EDIT: Beans that you declare in your config for your DispatcherServlet are not going to be available to any beans you declare or component scan in your contextConfigLocation config files. So in this case, if you're setting up your JPA config in your config file that you load for your DispatcherServlet there is no way to wire that in to beans your declare in your security config. You need to move any "core" bean config like that (datasource config, db connection pool config, JPA/Hibernate config, repository/service component scanning, etc.) into a config file that you load via the contextConfigLocation. Then that stuff will be available both to your security beans and your MVC beans. I think generally the idea is to only load MVC specific beans in your DispatcherServlet config (e.g. Controllers, views, request handlers, request scoped beans, etc.). That way you ensure you have a clean separation between MVC code and non-MVC code, with only a one-way dependency from the MVC code to the "core" code, and no dependencies on MVC code in your "core" code. This helps make your code more modular, and makes it easier to reuse your "core" code in other ways, specifically in unit tests.
(Original comment text was asking about how the security config is loaded, if it's in the contextConfigLocation or somewhere else.)

What is #Service in Spring MVC

If I use #Service on a service class, do I need to make a service class bean in my servlet xml file or do I have to do both?

You don't have to declare a bean in your context file if you:
1) Annotate the class with:
#Component, #Service, #Controller or #Repository
2) Include the context:component-scan element in your context file like this:
<context:component-scan base-package="your.package" />
Hope that helps.

Last time I looked (Spring 2.5) #Service was a marker annotation subclassed from #Component, but with no additional behaviour. Which means that beans tagged with #Service become candidates for auto detection if you are using annotation-based configuration via classpath scanning.
As per the docs, the intention is that this annotation might include service layer specific functionality in future Spring releases. It can also act as an AOP point cut for all of your service layer components.

Spring configuration in GWT Project?

I am developing a GWT-Spring-Hibernate project and I want to use Spring Autowired annotation in GWT Service Servlet but my autowired annotated service is not injected. it is null. Is there a configuration detail that I missed?
I add
<context:annotation-config />
<context:component-scan base-package="com.org" />
to my ApplicationContext.xml and I have annotated my service as #Service("myService")
#Autowired
MyService myService; // This is null so WHY?

You need to "autowire" your RPC servlets during initialization. Take a look here http://code.google.com/p/gwt-spring-starter-app/

Well, the class where the #Autowired annotation resides should also be in the spring context (i.e. annotated with #Component), but I doubt it will work if it is a GWT (i.e. client-side) class.

Is class you're trying to inject your service into actually a bean declared in Spring context? It should be, auto-wiring won't work otherwise.
It can either be declared explicitly or, provided that it's somewhere within your "com.org" hierrarchy it will be detected automatically IF it's annotated as #Component or one of other stereotypes provided by Spring.

How to inject a Spring bean into a Seam context?

I need to inject a Spring bean into a Seam context. Unless I declare the spring bean as a EJB, I cannot get it injected into other seam-managed components. But when I do this, all the spring injected fields are usless cause Seam creates new instances at run-time.
I also tried to add the <seam:component/> element to the spring bean definition and tried to inject it in the container with the #In("beanId") annotation in the target class but I always end up with a NullpointerException...
EDIT:
I read the online articles and did as they say. My spring component is also added to the seam context (I can tell, cause when I define one with the same ID in seam, it complains). Looks like #In is not picking up....

Have you read this chapter? It should tell you exactly what to do.

Raoul,
Although i do not use Seam along with Spring, chapter 15 of Seam In Action books talks about Spring integration. It is free and is updated.
You have said
I also tried to add the element to the spring bean definition and tried to inject it in the container with the #In("beanId")
Seam in Action book says
The EL expression used in the #In annotation, #{tournamentManager}, resolves to an equivalently named bean in the Spring container, courtesy of the delegating variable resolver
Do you have to use #In("#{beanId}") instead of #In("beanId"), do not ?
I have seen
By default, <seam:component/> will create a STATELESS Seam component with class and name provided in the bean definition.
<bean id="someSpringBean" class="SomeSpringBeanClass" scope="prototype">
<seam:component/>
</bean>
And
The scope attribute of <seam:component/> may be used if you wish the Spring bean to be
managed in a particular Seam scope. The Spring bean must be scoped to prototype if the
Seam scope specified is anything other than STATELESS.
Have you done as above ?

I have a project using Seam + Spring and I have to set #In(create=true) when I want to inject a Spring bean into my Seam component otherwise I get a NullPointerException, you should try it.

I got the same problem as yours. I followed strictly the "Chapter 27. Spring Framework integration" in seam ref. document. But my spring bean was never got injected to seam component. And finally, I found out I had the #BypassInterceptors in my seam component. By removing that annotation, my spring bean was successfully injected. Then I realized that, dependency injection is handled by seam BijectionInterceptor. Thus, the #BypassInterceptors will effectively bypass this filter :)