静态内部类的有关问题

//: net/mindview/util/Directory.java// Produce a sequence of File objects that match a// regular expression in either a local directory,// or by walking a directory tree.package net.mindview.util;import java.util.regex.*;import java.io.*;import java.util.*;public final class Directory {  public static File[]  local(File dir, final String regex) {    return dir.listFiles(new FilenameFilter() {      private Pattern pattern = Pattern.compile(regex);      public boolean accept(File dir, String name) {        return pattern.matcher(          new File(name).getName()).matches();      }    });  }  public static File[]  local(String path, final String regex) { // Overloaded    return local(new File(path), regex);  }  // A two-tuple for returning a pair of objects:  public static class TreeInfo implements Iterable<File> {    public List<File> files = new ArrayList<File>();    public List<File> dirs = new ArrayList<File>();    // The default iterable element is the file list:    public Iterator<File> iterator() {      return files.iterator();    }    void addAll(TreeInfo other) {      files.addAll(other.files);      dirs.addAll(other.dirs);    }    public String toString() {      return "dirs: " + PPrint.pformat(dirs) +        "\n\nfiles: " + PPrint.pformat(files);    }  }  public static TreeInfo  walk(String start, String regex) { // Begin recursion    return recurseDirs(new File(start), regex);  }  public static TreeInfo  walk(File start, String regex) { // Overloaded    return recurseDirs(start, regex);  }  public static TreeInfo walk(File start) { // Everything    return recurseDirs(start, ".*");  }  public static TreeInfo walk(String start) {    return recurseDirs(new File(start), ".*");  }  static TreeInfo recurseDirs(File startDir, String regex){    TreeInfo result = new TreeInfo();    for(File item : startDir.listFiles()) {      if(item.isDirectory()) {        result.dirs.add(item);        result.addAll(recurseDirs(item, regex));      } else // Regular file        if(item.getName().matches(regex))          result.files.add(item);    }    return result;  }  // Simple validation test:  public static void main(String[] args) {    if(args.length == 0)      System.out.println(walk("."));    else      for(String arg : args)       System.out.println(walk(arg));  }} ///:~

public class Test {    public static void main(String[] args) {        new Inner();    }    static class Inner {        Inner() {            System.out.println("你猜我是谁");        }    }}