collections
// sort
Collections.sort(List, Comparator);
e.g.
http://www.dreamsyssoft.com/java-8-lambda-tutorial/comparator-tutorial.php
old way:
Collections.sort(users, new Comparator<User>() {
public int compare(User u1, User u2) {
return u1.id.compareTo(u2.id);
}
});
new way in java8:
Collections.sort(users, (User u1, User u2) -> u1.id.compareTo(u2.id));