Java 8 Distinct by property

Question

In Java 8 how can I filter a collection using the Stream API by checking the distinctness of a property of each object?

For example I have a list of

Answer 1

If you want to List of Persons following would be the simple way

Set set = new HashSet<>(persons.size());
persons.stream().filter(p -> set.add(p.getName())).collect(Collectors.toList());

Additionally, if you want to find distinct or unique list of names, not Person , you can do using following two method as well.

Method 1: using distinct

persons.stream().map(x->x.getName()).distinct.collect(Collectors.toList());

Method 2: using HashSet

Set set = new HashSet<>();
set.addAll(person.stream().map(x->x.getName()).collect(Collectors.toList()));