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Getting Stuff from the Container

Generally speaking the only way to get a container controlled resource is via dependency injection or lookup from within a container managed component. Dependency injection can be configure equally via xml or annotations

InitialContext Lookups

  • Server side beans should access other beans on the server via the default no args constructor (EJB 3 spec 15.3.1 Bean Provider's Responsibilities), in order to propagate the security .
  • Container side lookup names must be preceded with java:comp/env, as in java:comp/env/myBean. e.g. 
    initialContext.lookup("java:comp/env/beanName")
  • note that java:comp/env/ is empty by default, and you need to declare your references, whether via xml or annotations
    • Declared via annotations 
      @EJB(name="myBean", beanInterface = IMyBean.class)
public class DependentBean ....
    • Declared via xml INCOMPLETE
  • Clients is a good reference for more complex lookups, including authentication.

Injection

Some important things to realize about dependency injections.

  • @EJB IMyBean myBean is syntactic sugar for lookups (as follows), and is overridden by xml 
    initialContext = new InitialContext();
initialContext.lookup("java:comp/env/beanName")
  • EJB Refs is a good reference for injection via xml or annotations
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