Here we can Sort a List Using compareTo() and Method Reference.
- In this example, we will sort a List<Integer> in Java using the Collections.sort() method.
- First, we use a lambda expression with the compareTo() method.
- Then, we use a method reference to sort the list in a shorter and cleaner way.
- Both approaches produce the same sorted output.
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
public class SortWithCompareTo {
public static void main(String[] args) {
List<Integer> list = Arrays.asList(15, 24, 40, 2, 19);
//Method 1: Sorting using lambda expression:-
System.out.println("Sorting with lambda expression and compareTo():- ");
Collections.sort(list, (n1, n2) -> n1.compareTo(n2));
list.forEach(System.out::println);
//ethod 2: Sorting using method reference:-
System.out.println("Sorting with Method Reference and compareTo():- ");
Collections.sort(list, Integer::compareTo);
list.forEach(System.out::println);
}
}
Output :-
Sorting with lambda expression and compareTo():-
2
15
19
24
40
Sorting with Method Reference and compareTo():-
2
15
19
24
40
FAQ
Why can we use Integer::compareTo directly?
Integer::compareTo is a method reference to the compareTo() instance method of the Integer class.It is used as a comparator in Collections.sort() to compare two integer values in ascending order.