Comparator naturalOrder() method in Java with examples

Last Updated : 29 Apr, 2019

The naturalOrder() method of Comparator Interface in Java returns a comparator that use to compare Comparable objects in natural order. The returned comparator by this method is serializable and throws NullPointerException when comparing null.

Syntax:

static <T extends Comparable<T>> 
    Comparator<T> naturalOrder()

Parameters: This method accepts nothing.

Return value: This method returns a comparator that imposes the natural ordering on Comparable objects.

Below programs illustrate naturalOrder() method:
Program 1:

// Java program to demonstrate 
// Comparator.naturalOrder()  method 
  
import java.util.Arrays; 
import java.util.Comparator; 
import java.util.List; 
  
public class GFG { 
    public static void main(String... args) 
    { 
  
        List<Integer> values 
            = Arrays.asList(212, 324, 
                            435, 566, 
                            133, 100, 121); 
  
        // naturalOrder is a static method 
        values.sort(Comparator.naturalOrder()); 
  
        // print sorted number based on natural order 
        System.out.println(values); 
    } 
} 

The output printed on console of IDE is shown below.
Output:

Program 2:

// Java program to demonstrate 
// Comparator.naturalOrder()  method 
  
import java.util.Arrays; 
import java.util.Comparator; 
import java.util.List; 
  
public class GFG { 
    public static void main(String... args) 
    { 
  
        List<String> stringList 
            = Arrays.asList("Aman", "Kajal", 
                            "Joyita", "Das"); 
  
        System.out.println("Before sorting:"); 
        stringList.forEach(System.out::println); 
  
        stringList.sort(Comparator.naturalOrder()); 
        System.out.println("\nAfter sorting:"); 
        stringList.forEach(System.out::println); 
    } 
} 