code: public static String getFirstSubstring(final String inputString,
              final String startingWith, final String endingWith) {
          if (!inputString.contains(startingWith)
                  || !inputString.contains(endingWith)) {
              return null;
          }
          final int startIndex = inputString.indexOf(startingWith);
  
          if (!((startIndex + 1) < inputString.length())) {
              return null;
          }
  
          final int endIndex = inputString.indexOf(endingWith, startIndex + 1)
                  + 1;
          if (startIndex > endIndex || startIndex < 0 || endIndex < 0) {
              return null;
          }
          return inputString.substring(startIndex, endIndex);
      }
docs: gets the first substring which starts and ends with the given values.
  
  @param inputString
  the string from which the substring will be
  extracted.
  @param startingWith
  to match the starting substring
  @param endingWith
  to match the ending substring
  @return the substring which starts and ends with the given
  {@code startingWith} and {@code endingWith} values. Or returns
  null if it doesn't contain.
  @author WFF
  @since 1.0.0