code: public static Pattern createResourceFilesPattern(String fileName, String fileExtension) {
  		return Pattern.compile(createResourceFilesRegex(fileName, fileExtension));
  	}
docs: Returns a {@code Pattern} to match source and translated resource filenames with the given {@code fileName} and
  {@code fileExtension}.
  <p>
  For example, with {@code fileName} as "Messages" and {@code fileExtension} as ".properties" the returned pattern would
  match:
  <ul>
  <li>Messages.properties</li>
  <li>Messages_en.properties</li>
  <li>Messages_en_GB.properties</li>
  </ul>
  <p>
  The pattern is case-sensitive.
  
  @param fileName the name of the resource files
  @param fileExtension the extension of the resource files
  @return the {@code Pattern} to match resource filenames
  @throws IllegalArgumentException if the given {@code fileName} or {@code fileExtension} is {@code null}.
  @see #createResourceFilesRegex(String, String)
  @see #LANGUAGE_LOCALE_REGEX
  @see #COUNTRY_LOCALE_REGEX
  @since 2.4.0