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 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:
// 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);
}
} |
The output printed on console is shown below.
Output:
References: https://docs.oracle.com/javase/10/docs/api/java/util/Comparator.html#reverseOrder()