Directory Traversal and Empty Directory Issue. Please Help!

Question

Hi
I am building an application which is aimed at traversing the entire hard disk or a given folder and extract files from the folder, sub-folders and so on. I am able to currently traverse the disk and able to gain access to the files which are nested several layers of directories. The issue I am facing is that when I reach an empty directory, it throws a NullPointerException. I have tried using all kinds of methods like dir.exists() and have also tried to check for whether the number files in the directory is > 0, but the exception is still bugging me. I would require any help I can get.
Here is the code:
public class myFileReader{
    void myRecursiveMethod(File dir) {
        File eachFile;
        File[] files = dir.listFiles();
        for (int i = 0;i < files.length; i++) {
            if (files.isDirectory()) {
if (files[i].list().length > 0) { // I am not sure if this is the right way to go about it. This is one of the ways I tried.
eachFile = (File)files[i];
myRecursiveMethod(eachFile);
System.out.println("Directory: " + eachFile);
} else if (files[i].isFile()) {
System.out.println("Files: " + files[i]);
public static void main(String[]args) throws Exception {
File dir = new File("C://");
myFileReader mfr = new myFileReader();
mfr.myRecursiveMethod(dir);
Hope to get some responses soon.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Answer 1

kajbj wrote:
One line throws the exception, and why aren't you checking what list() returns? It can return null.
and the whole of this
              if (files.list().length > 0) { // I am not sure if this is the right way to go about it. This is one of the ways I tried.
eachFile = (File)files[i];
myRecursiveMethod(eachFile);
System.out.println("Directory: " + eachFile);
} can be replaced by myRecursiveMethod(files[i]);
System.out.println("Directory: " + files[i]);
Edited by: sabre150 on May 23, 2009 8:49 AM