Consider using Iterable/Collection where possible.

[marcus-talbot42]

In many cases, we use a List simply as the default collection, rather than for a specialised purpose. In such cases, it would be worthwhile to use an Iterable, or a Collection, to improve the flexibility of the library.

E.g.

public interface Configuration {
    ...
    List<String> getDownsizeTarget();
    ...
}

In this case, the method likely does not need to return a List. In all likelihood, Iterable would be an acceptable substitution.