List all Files from a Directory (or Subdirectory)

import java.io.File;

public class ListFilesUtil {
 
    /**
     * List all the files and folders from a directory
     * @param directoryName to be listed
     */
    public void listFilesAndFolders(String directoryName){
 
        File directory = new File(directoryName);
 
        //get all the files from a directory
        File[] fList = directory.listFiles();
 
        for (File file : fList){
            System.out.println(file.getName());
        }
    }
 
    /**
     * List all the files under a directory
     * @param directoryName to be listed
     */
    public void listFiles(String directoryName){
 
        File directory = new File(directoryName);
 
        //get all the files from a directory
        File[] fList = directory.listFiles();
 
        for (File file : fList){
            if (file.isFile()){
                System.out.println(file.getName());
            }
        }
    }
 
    /**
     * List all the folder under a directory
     * @param directoryName to be listed
     */
    public void listFolders(String directoryName){
 
        File directory = new File(directoryName);
 
        //get all the files from a directory
        File[] fList = directory.listFiles();
 
        for (File file : fList){
            if (file.isDirectory()){
                System.out.println(file.getName());
            }
        }
    }
 
    /**
     * List all files from a directory and its subdirectories
     * @param directoryName to be listed
     */
    public void listFilesAndFilesSubDirectories(String directoryName){
 
        File directory = new File(directoryName);
 
        //get all the files from a directory
        File[] fList = directory.listFiles();
 
        for (File file : fList){
            if (file.isFile()){
                System.out.println(file.getAbsolutePath());
            } else if (file.isDirectory()){
                listFilesAndFilesSubDirectories(file.getAbsolutePath());
            }
        }
    }
 
    public static void main (String[] args){
 
        ListFilesUtil listFilesUtil = new ListFilesUtil();
 
        final String directoryLinuxMac ="/Users/loiane/test";
 
        //Windows directory example
        final String directoryWindows ="C://test";
 
        listFilesUtil.listFiles(directoryLinuxMac);
    }
}