Thinking in java(I/O)

    public void testListFiles()
    {
        File dir = new File(".");
        File[] subs = dir.listFiles();
        for(File sub:subs)
        {
            System.out.println(sub);
        }
    }

    public void testFileFilter()
    {
        File dir = new File(".");
        File[] subs = dir.listFiles(
                new FileFilter()
               {
                    @Override
                    public boolean accept(File file) {
                        return file.getName().endsWith(".txt");
                    }
        });
        for(File sub:subs)
        {
            System.out.println(sub);
        }
    }