list all files from directories and subdirectories in Java

Question

What would be the fastest way to list the names of files from 1000+ directories and sub-directories?

EDIT; The current code I use is:

import java.io.File;  public class DirectoryReader {    static int spc_count=-1;    static void Process(File aFile) {     spc_count++;     String spcs = "";     for (int i = 0; i < spc_count; i++)       spcs += " ";     if(aFile.isFile())       System.out.println(spcs + "[FILE] " + aFile.getName());     else if (aFile.isDirectory()) {       System.out.println(spcs + "[DIR] " + aFile.getName());       File[] listOfFiles = aFile.listFiles();       if(listOfFiles!=null) {         for (int i = 0; i < listOfFiles.length; i++)           Process(listOfFiles[i]);       } else {         System.out.println(spcs + " [ACCESS DENIED]");       }     }     spc_count--;   }    public static void main(String[] args) {     String nam = "D:/";     File aFile = new File(nam);     Process(aFile);   }  } 

Answer 1

As this answer shows up on top of google, i'm adding a java 7 nio solution for listing all files and directories, it is takes about 80% less time on my system.

try {     Path startPath = Paths.get("c:/");     Files.walkFileTree(startPath, new SimpleFileVisitor<Path>() {         @Override         public FileVisitResult preVisitDirectory(Path dir,                 BasicFileAttributes attrs) {             System.out.println("Dir: " + dir.toString());             return FileVisitResult.CONTINUE;         }          @Override         public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {             System.out.println("File: " + file.toString());                 return FileVisitResult.CONTINUE;         }          @Override         public FileVisitResult visitFileFailed(Path file, IOException e) {             return FileVisitResult.CONTINUE;         }     }); } catch (IOException e) {     e.printStackTrace(); }