Get list of attributes of an object in an List

Question

When there is an List, is there a possibility of getting List of all person.getName() out of that? Is there an prepared call for that

Answer 1

Java 8 and above:

List namesList = personList.stream()
                                   .map(Person::getName)
                                   .collect(Collectors.toList());

If you need to make sure you get an ArrayList as a result, you have to change the last line to:

                                    ...
                                    .collect(Collectors.toCollection(ArrayList::new));

---

Java 7 and below:

The standard collection API prior to Java 8 has no support for such transformation. You'll have to write a loop (or wrap it in some "map" function of your own), unless you turn to some fancier collection API / extension.

(The lines in your Java snippet are exactly the lines I would use.)

In Apache Commons, you could use CollectionUtils.collect and a Transformer

In Guava, you could use the Lists.transform method.