code: public static List<String> getFilesInFolder(String folder, String ext) {
  		// tryto find using normal file system lookup
  		List<String> files = new Vector<>();
  		File dir = new File(folder);
  		if (dir.exists() && dir.isDirectory()) {
  			String[] list = dir.list();
  			for (String file : list) {
  				if (file.endsWith(ext)) {
  					files.add(file);
  				}
  			}
  		}
  		return files;
  	}
docs: Gets the files in folder.
  
  @param folder the folder
  @param ext    the ext
  @return the files in folder