public void pathRecurse(String folderPath, List<String> targetList)
	{
        File musicFolder = new File(folderPath);

        if(!musicFolder.exists()) {
            musicFolder.mkdirs();
        }

        File[] abstractPaths = musicFolder.listFiles();

        for(File path: abstractPaths)
        {   //only add it to the list if it's a .mp3 file
            if(path.isFile() && path.getPath().matches("^.+?\\.mp3")) {
                targetList.add(path.getPath());
            } else if(path.isDirectory()) { //otherwise we must go deeper
                pathRecurse(path.getPath(), targetList);
            } // or ignore it
        }
	}