Is there an easy way to autowire empty collection if no beans present in Spring?

Question

If I have @Autowired List beans; and no beans of SomeBeanClass, I get:

No matching bean of type [SomeBe

Answer 1

There are a few options with Spring 4 and Java 8:

@Autowired(required=false)
private List providers = new ArrayList<>();

You can also use java.util.Optional with a constructor:

@Autowired
public MyClass(Optional> opFoo) {
    this.foo = opFoo.orElseGet(ArrayList::new);
}

You should also be able to autowire an a field with Optional> opFoo;, but I haven't used that yet.