File class question

Question

Hi all,
I've been playing with the File class (as a way of learning about it) and am confused about the behaviour of the following code.
This class is uses recursion as a way of getting a file structure.
import java.io.File;
public class FileTest {
    public static void main(String[] args) {
        if (args.length == 0) {
            return;
        File file = new File(args[0]);
        processFileList(file);
    public static void processFileList(File f) {
        if (f.isDirectory()) {
            System.out.println("found directory: " + f.getName());
            String fileList[] = f.list();
            for (int i=0; i < fileList.length; i++) {
                File newF = new File(fileList);
if (newF.isFile()) {
System.out.println("Found file in list: " + newF.getName());
} else {
System.out.println("Found new directroy is list: " + newF.getName());
processFileList(newF);
} else {
System.out.println("Found file: " + f.getName());
The command line I use is java FileTest testdir
The output from the code is:
found directory: testdir
Found file in list: FileTest.class
Found file in list: Hello.class
Found file in list: LogTest.class
Found new directroy is list: testdir2
Found file: testdir2
The file structure being used is testdir, which contains the three class files and a directory called testdir2. testdir2 contains some java files.
I don't understand why testdir2 is recognised as not being a file, but is not recognised as being a directory. I changed the code to use isDirectory() rather than isFile(), but the results were similar, testdir2 is not recognised as a directory.
Any ideas? Thanks,
dan

Answer 1

When you instantiate the class java.io.File from a String you should use a pathname or depict the parent directory as well as the abstract file name. Or you could use the method listFiles() of the File class.
File[] fileList = f.listFiles();