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

import java.io.File;
import java.io.IOException;

import org.apache.commons.io.filefilter.FullClassNameMatcher;

public class Example {
    public static void main(String[] args) throws IOException {
        File file = new File("example.class");
        FullClassNameMatcher matcher = new FullClassNameMatcher("example.class");
        boolean isMatched = matcher.match(file);
        System.out.println(isMatched);
    }
}

This example creates a FullClassNameMatcher object with the class name "example.class" and uses it to match a File object representing the file "example.class". The match method is called on the matcher object with the file object passed as an argument. If the file name and the class name match, it returns true otherwise false.

You can also use your own implementation of the FileFilter by extending the FullClassNameMatcher class and passing it to the super class constructor, you can use the accept method to execute your own logic, for example, you can use it to check the class files with a specific package name, or for any other purpose.

Note that, the FullClassNameMatcher is not intended to be used as a general-purpose class, it is intended to be used only in situations where you need to filter the files based on their class names.