How to list all files in a directory and its subdirectories in hadoop hdfs

If you are using hadoop 2.* API there are more elegant solutions:

    Configuration conf = getConf();
    Job job = Job.getInstance(conf);
    FileSystem fs = FileSystem.get(conf);

    //the second boolean parameter here sets the recursion to true
    RemoteIterator<LocatedFileStatus> fileStatusListIterator = fs.listFiles(
            new Path("path/to/lib"), true);
    while(fileStatusListIterator.hasNext()){
        LocatedFileStatus fileStatus = fileStatusListIterator.next();
        //do stuff with the file like ...
        job.addFileToClassPath(fileStatus.getPath());
    }