list all files in the folder and also sub folders

> Possible Duplicate:
> List all files from a directory recursively with Java

How can i return a file array that include all files on the folder and also sub folders my method just work for folder and it doesn't include sub folders .

public File[] listf(String directoryName) {
	
	// .............list file
	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()) {
			listf(file.getAbsolutePath());
		}
	}
	System.out.println(fList);
	return fList;
}                        

Using you current code, make this tweak:

public void listf(String directoryName, List<File> files) {
    File directory = new File(directoryName);

    // Get all files from a directory.
    File[] fList = directory.listFiles();
    if(fList != null)
        for (File file : fList) {      
            if (file.isFile()) {
                files.add(file);
            } else if (file.isDirectory()) {
                listf(file.getAbsolutePath(), files);
            }
        }
}

Use FileUtils from Apache commons.

listFiles

public static Collection<File> listFiles(File directory,
                                         String[] extensions,
                                         boolean recursive)
Finds files within a given directory (and optionally its subdirectories) which match an array of extensions.
Parameters:
directory - the directory to search in
extensions - an array of extensions, ex. {"java","xml"}. If this parameter is null, all files are returned.
recursive - if true all subdirectories are searched as well
Returns:
an collection of java.io.File with the matching files

You can return a List instead of an array and things gets much simpler.

	public static List<File> listf(String directoryName) {
	    File directory = new File(directoryName);

	    List<File> resultList = new ArrayList<File>();

	    // get all the files from a directory
	    File[] fList = directory.listFiles();
	    resultList.addAll(Arrays.asList(fList));
	    for (File file : fList) {
	        if (file.isFile()) {
	            System.out.println(file.getAbsolutePath());
	        } else if (file.isDirectory()) {
	            resultList.addAll(listf(file.getAbsolutePath()));
	        }
	    }
	    //System.out.println(fList);
	    return resultList;
	}