code: static public BigDecimal decodeDecimal(final ByteBuffer bb) {
          final int scale = bb.get();
          final int precisionBytes = bb.get();
          final byte[] bytes = new byte[precisionBytes];
          bb.get(bytes);
          return new BigDecimal(new BigInteger(bytes), scale);
      }
docs: Read a decimal according to the Four Dot Four encoding specification.
  
  @param bb
  ByteBuffer containing Export stream data
  @return decoded BigDecimal value