code: public static String readShortString(ByteBuffer buffer) {
          short size = buffer.getShort();
          if (size < 0) {
              return null;
          }
          byte[] bytes = new byte[size];
          buffer.get(bytes);
          return fromBytes(bytes);
      }
docs: read bytes with a short sign prefix(mark the size of bytes)
  
  @param buffer data buffer
  @return string result(encoding with UTF-8)
  @see #writeShortString(ByteBuffer, String)