code: public static File getDir(File parent, String item) {
  		File dir = new File(parent, item);
  		return (dir.exists() && dir.isDirectory()) ? dir : null;
  	}
docs: Returns a subdirectory of a given directory; the subdirectory is expected to already exist.
  @param parent the directory in which to find the specified subdirectory
  @param item the name of the subdirectory
  @return the subdirectory having the specified name; null if no such directory exists or
  exists but is a regular file.