Should I use EJB or Inject

Question

I have found this question  What is the difference between  Inject and  EJB but I did not get any wiser  I have not done Java EE before nor do I have experience with dependency injection so I do not understand what I should use   Is  EJB an old way of injecting  Is the injection done by the EJB container when using this annotation while using  Inject use the new CDI framework  Is that the difference and should I be using  Inject instead of  EJB if this is the case

User · Answer

Update  This answer may be incorrect or out of date  Please see comments for details   I switched from  Inject to  EJB because  EJB allows circular injection whereas  Inject pukes on it   Details  I needed  PostConstruct to call an  Asynchronous method but it would do so synchronously  The only way to make the asynchronous call was to have the original call a method of another bean and have it call back the method of the original bean  To do this each bean needed a reference to the other -- thus circular   Inject failed for this task whereas  EJB worked

User · Answer

The  EJB is used to inject EJB s only and is available for quite some time now   Inject can inject any managed bean and is a part of the new CDI specification  since Java EE 6    In simple cases you can simply change  EJB to  Inject  In more advanced cases  e g  when you heavily depend on  EJB s attributes like beanName  lookup or beanInterface  than in order to use  Inject you would need to define a  Producer field or method   These resources might be helpful to understand the differences between  EJB and  Produces and how to get the best of them   Antonio Goncalves  blog  CDI Part I CDI Part II CDI Part III    JBoss Weld documentation  CDI and the Java EE ecosystem  StackOverflow  Inject  EJB bean based on conditions

User · Answer

Inject can inject any bean  while  EJB can only inject EJBs  You can use either to inject EJBs  but I d prefer  Inject everywhere

User · Answer

Here is a good discussion on the topic   Gavin King recommends  Inject over  EJB for non remote EJBs     http   www seamframework org 107780 lace  or   https   web archive org web 20140812065624 http   www seamframework org 107780 lace     Re  Injecting with  EJB or  Inject          Nov 2009  20 48 America New York   Link Gavin King             That error is very strange  since EJB local references should always   be serializable  Bug in glassfish  perhaps       Basically   Inject is always better  since   it is more typesafe  it supports  Alternatives  and it is aware of the scope of the injected object        I recommend against the use of  EJB except for declaring references to   remote EJBs    and     Re  Injecting with  EJB or  Inject          Nov 2009  17 42 America New York   Link Gavin King      Does it mean  EJB better with remote EJBs           For a remote EJB  we can t declare metadata like qualifiers     Alternative  etc  on the bean class  since the client simply isn t   going to have access to that metadata  Furthermore  some additional   metadata must be specified that we don t need for the local case    global JNDI name of whatever   So all that stuff needs to go   somewhere else  namely the  Produces declaration

User · Answer

It may also be usefull to understand the difference in term of Session Bean Identity when using  EJB and  Inject  According to the specifications the following code will always be true    EJB Cart cart1   EJB Cart cart2      if  cart1 equals cart2        this test must return true        Using  Inject instead of  EJB there is not the same   see also stateless session beans identity for further info

User · Answer

Injection already existed in Java EE 5 with the  Resource   PersistentUnit or  EJB annotations  for example  But it was limited to certain resources  datasource  EJB        and into certain components  Servlets  EJBs  JSF backing bean         With CDI you can inject nearly anything anywhere thanks to the  Inject annotation

[java] Should I use @EJB or @Inject

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