what is natural order in java

// 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); 
    } 
}