private File[] buildAvdFilesList() throws AndroidLocationException {
File folder = new File(getBaseAvdFolder());
// ensure folder validity.
if (folder.isFile()) {
throw new AndroidLocationException(
String.format("%1$s is not a valid folder.", folder.getAbsolutePath()));
} else if (folder.exists() == false) {
// folder is not there, we create it and return
folder.mkdirs();
return null;