CODEWITHSUNDEEP
jakarta-eedependency-injectionejb-3.1
Iori Yagami
Iori Yagami

Reputation: 406

NullPointerException on @Ejb dependency injection

I have an Ear project, in which I put an EJB project and a simple Web project. I call the EJB in a managedBean and it just works fine with the lookup thing. I call the EJB in the same managedBean and it doesn't instantiate. The web project supports CDI (I checked the support option) Here's the code of the EJB : 

@Stateless
@LocalBean
public class MyTestBean implements MyTestBeanRemote, MyTestBeanLocal {

/**
 * Default constructor. 
 */
public MyTestBean() {
    // TODO Auto-generated constructor stub
}

public String message() {
    return "This is my Test bean";
}
}

@Local
public interface MyTestBeanLocal {
    String message();
}

And here's the code of the calling bean : 

@ManagedBean(name="testBean")
public class TestBean {

private String hello = "Hello it is me";

@EJB
private MyTestBeanLocal myTest;

public TestBean() {
    hello = myTest.message();
}
}

The "myTest" variable is null. What am I missing?

Upvotes: 2

Views: 1709

Answers (1)

maress
maress

Reputation: 3533

You cannot use the injected instance if it is a field injection.

If you want to use the the injected instance in the constructor, you need to do a constructor injection (I'm unsure if EJB supports constructor injection)

@Inject //will only work if you are defining EJB in the same war file
public TestBean(MyTestBeanLocal beanLocal) {
  this.beanLocal = beanLocal;
  hello = myTest.message();
}

otherwise do whatever you need to do a @postconstruct. This is guaranteed to be called before the bean is put into service.

@PostConstruct
public void postConstruct() {
    hello = myTest.message();
}

Upvotes: 2

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