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

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

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

In this example, we are sorting an array of File objects using the LastModifiedFileComparator.LASTMODIFIED_COMPARATOR constant. This comparator sorts files based on their last modified timestamps. The Arrays.sort() method is used to sort the files array using the LastModifiedFileComparator.LASTMODIFIED_COMPARATOR constant as the comparator.

You can also pass a boolean value as argument to the LastModifiedFileComparator constructor indicating whether the sort should be done in reverse order. For example:

LastModifiedFileComparator comparator = new LastModifiedFileComparator(true);

This will sort the files in reverse order of their last modified timestamps.

It's worth noting that the LastModifiedFileComparator class is an extension of AbstractFileComparator class, that uses the File class's natural ordering to compares files and sorts them based on their last modified timestamps, in the order specified in the constructor.