Here is an example of how to use the ReverseFileComparator class from the org.apache.commons.io package in Java:

import java.io.File;
import org.apache.commons.io.comparator.LastModifiedFileComparator;
import org.apache.commons.io.comparator.ReverseComparator;

public class Example {
    public static void main(String[] args) {
        File[] files = ...
        Arrays.sort(files, new ReverseComparator(LastModifiedFileComparator.LASTMODIFIED_COMPARATOR));
    }
}

In this example, we are using the ReverseComparator class to sort an array of File objects in reverse order. The ReverseComparator class takes another comparator as a constructor argument, and uses it to sort the files in reverse order. In this example, we pass the LastModifiedFileComparator.LASTMODIFIED_COMPARATOR constant, which sorts files based on their last modified timestamps, but in reverse order.

You can use ReverseComparator with any other comparator like SizeFileComparator, NameFileComparator, PathFileComparator etc and it will sort the files in reverse order.

It's worth noting that the ReverseComparator class is an extension of Comparator class, that takes another comparator as an argument and inverts the order of the comparison.