code: @Nonnegative
    private static int _appendNextCharacterAndAdvanceLoop (@Nonnull final String sLine,
                                                           @Nonnull final StringBuilder aSB,
                                                           @Nonnegative final int nIndex)
    {
      aSB.append (sLine.charAt (nIndex + 1));
      return nIndex + 1;
    }
docs: Appends the next character in the line to the {@link StringBuilder}.
  
  @param sLine
  line to process
  @param aSB
  contains the processed character
  @param nIndex
  current position in the line.
  @return new position in the line.