code: public static LibertyVersion valueOf(String versionString) {
          if (versionString == null) {
              return null;
          }
          versionString = versionString.trim();
          Matcher versionMatcher = VALID_VERSION.matcher(versionString);
          if (!versionMatcher.matches()) {
              return null;
          }
          return new LibertyVersion(Integer.parseInt(versionMatcher.group(1)), Integer.parseInt(versionMatcher.group(2)), Integer.parseInt(versionMatcher.group(3)), Integer.parseInt(versionMatcher.group(4)));
      }
docs: Parses the supplied string into a LibertyVersion. Will return <code>null</code> if the string is not a valid version string.
  
  @param versionString The string to parse
  @return The version