Directories

import java.nio.filesystems.*;
import java.io.*;

public class FileSystemLister {

  public static void main(String[] args) throws IOException {

    File[] roots = File.listRoots();
    for (int i = 0; i < roots.length; i++) {
       FileReference ref = roots[i].toFileReference();
       Directory root = ref.openDirectory();
       list(root);
    }

  }

  public static void list(Directory dir) {
    try {
      for (Directory.Entry entry : dir) {
         FileReference ref = entry.asFileReference();
         System.out.println(entry.getName());
         try {
           Directory child = ref.openDirectory();
           // aliases?
           list(child);
         }
         catch (NotDirectoryException ex) {
           // There must be a better way to tell 
           // if a file is a directory before we open it
         }
      }
    } 
    finally {
      dir.close();
    }
  }
  

}