Comparator reverseOrder() method in Java with examples

0 0 1 minute read

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

Syntax:

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

Parameters: This method accepts nothing.

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

Below programs illustrate reverseOrder() method:

Program 1:

Java

// Java program to demonstrate
// Comparator.reverseOrder()  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);
 
        // reverseOrder is a static method
        values.sort(Comparator.reverseOrder());
 
        // print sorted number based on reverse order
        System.out.println(values);
    }
}

The output printed on console of IDE is shown below.

Output:

Program 2:

Java

// Java program to demonstrate
// Comparator.reverseOrder()  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.reverseOrder());
        System.out.println("\nAfter sorting:");
        stringList.forEach(System.out::println);
    }
}