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

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

public class FileNameComparator extends AbstractFileComparator {
    public int compare(File file1, File file2) {
        return file1.getName().compareTo(file2.getName());
    }
}

In this example, we create a new class FileNameComparator that extends AbstractFileComparator. This class compares two File objects based on their file names. The compare method is overridden from the AbstractFileComparator class, and it takes two File objects as its parameters. The method compares the file names of the two files using the compareTo method, and returns the result.

You can use this comparator class in the following way:

File[] files = ...
Arrays.sort(files, new FileNameComparator());

This will sort the files based on their name.