code: protected static final Long parseUsingFallbacksWithColon(String text, DateTimeFormat timeFormat) {
          if (text.indexOf(':') == -1) {
              text = text.replace(" ", "");
              int numdigits = 0;
              int lastdigit = 0;
              for (int i = 0; i < text.length(); i++) {
                  char c = text.charAt(i);
                  if (Character.isDigit(c)) {
                      numdigits++;
                      lastdigit = i;
                  }
              }
              if (numdigits == 1 || numdigits == 2) {
                  // insert :00
                  int colon = lastdigit + 1;
                  text = text.substring(0, colon) + ":00" + text.substring(colon);
              }
              else if (numdigits > 2) {
                  // insert :
                  int colon = lastdigit - 1;
                  text = text.substring(0, colon) + ":" + text.substring(colon);
              }
              return parseUsingFallbacks(text, timeFormat);
          }
          else {
              return null;
          }
      }
docs: Attempts to insert a colon so that a value without a colon can
  be parsed.