code: public static final char parseChar(CharSequence cs, int beginIndex, int endIndex)
      {
          if (endIndex - beginIndex != 1)
          {
              throw new IllegalArgumentException("input length must be 1");
          }
          return cs.charAt(beginIndex);
      }
docs: Returns char from input.
  @param cs
  @param beginIndex the index to the first char of the text range.
  @param endIndex the index after the last char of the text range.
  @return
  @throws IllegalArgumentException if input length is not 1.