Here's an example of how to use the HiddenFileFilter class from the Apache Commons IO library to filter out hidden files in a directory:

import java.io.File;
import org.apache.commons.io.filefilter.HiddenFileFilter;

public class Main {
    public static void main(String[] args) {
        File dir = new File("/path/to/directory");
        File[] hiddenFiles = dir.listFiles((FileFilter) HiddenFileFilter.HIDDEN);

        for (File file : hiddenFiles) {
            System.out.println(file.getName());
        }
    }
}

In this example, /path/to/directory should be replaced with the path to the directory you want to search through. The listFiles method is called on the dir object, and it takes an instance of FileFilter as an argument. The HiddenFileFilter.HIDDEN constant is used to filter out hidden files. The filtered hidden files are stored in the hiddenFiles array, and their names are printed out using a for loop.