Collections - Beginning Java 8 Language Features - page 578

■ Java 8 added a default method called sort(Comparator<? super E> c) in the List<E> interface that allows
you to sort a List without using the Collections class.

Tip

The following snippet of code demonstrates how to sort a List :

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
...
List<String> list = new ArrayList<>();
list.add("John");
list.add("Richard");
list.add("Donna");
list.add("Ken");

System.out.println("List: " + list);

// Uses Comparable implementation in String to sort the list in natural order
Collections.sort(list);
System.out.println("Sorted List: " + list);

List: [John, Richard, Donna, Ken]
Sorted List: [Donna, John, Ken, Richard]

The following snippet of code sorts the same list in ascending order of the length of their elements using the
sort() method in the List interface:

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
...
List<String> list = new ArrayList<>();
list.add("John");
list.add("Richard");
list.add("Donna");
list.add("Ken");

System.out.println("List: " + list);

// Uses List.sort() method with a Comparator
list.sort(Comparator.comparing(String::length));
System.out.println("Sorted List: " + list);

List: [John, Richard, Donna, Ken]
Sorted List: [Ken, John, Donna, Richard]