code: public boolean isChecksumValid() {
          if(checksum == 0)
              return true;
  
          int crc = CRCUtils.getCRC(getHeader());
          if(data != null && data.length > 0) {
              crc = CRCUtils.getCRC(data, crc);
          }
  
          return (checksum == crc);
      }
docs: Is the checksum for the page valid?