Sort contact list by name using Java stream.sort() [duplicate]

Question

In my code I want to sort the contacts by their firstname, so I wrote the below method which is not working for me. Actually this code instead of giving me a sorted contact list it is giving me a normal unordered contactlist

public Set<Contact> sortContacts() {
    Set<Contact> sortedContacts = contactList.stream().sorted((c1, c2) -> c1.firstName.compareTo(c2.firstName)).collect(Collectors.toSet());
    return sortedContacts;
}

Answer 1

Each data structure has its own unique feature. A Set is an unordered list with no duplicate elements in it.

You need to use an Array or a List in order to keep the positions of your elements intact, such as in the case of sorting.

You can go through this blog to understand the difference between a Set and a List.

You can also modify the last chained method .collect(Collectors.toSet()) to .collect(Collectors.toList()), to acheive your desired result.