CDI constructor injection don't work with transient non-serializable dependencies

Question

I like the constructor injection of CDI a lot but now I found a usecase where constructor injection apparently doesn't work as expected.

In my example I have two classes. Class "BeanA" has no explicit scope defined and does not implement Serializable. Class "BeanB" is annotated with @SessionScoped and does implement Serializable.

public class BeanA{
}

@SessionScoped
public class BeanB implements Serializable{
    @Inject
    private BeanA beanA;
}

When I try to inject an instance of BeanA into BeanB of cource I get an UnserializableDependencyException from Weld because BeanA isn't serializable. This is the expected behaviour.

When I mark the field "beanA" with "transient" the injection works without problems:

@Inject
private transient BeanA beanA;

Now Weld doesn't throw any exceptions.

This is perfectly fine for me but my understanding problem comes when I like to get this working with constructor injection. When I do the following it doesn't work anymore:

@SessionScoped
public class BeanB implements Serializable{
    private transient BeanA beanA;

    @Inject
    public BeanB(BeanA beanA){
        this.beanA = beanA;
    }

    public BeanB(){}
}

With this code I get the UnserializableDependencyException again. I thought that constructor injection and field injection are more or less equivalent but obviously they aren't. What is my mistake?

Answer 1

That seems like a bug. Does everything work well if you make BeanA serializable? Also which version of Weld are you using?