code: public int compareTo(Block b) {
      //Wildcard generationStamp is NOT ALLOWED here
      validateGenerationStamp(this.generationStamp);
      validateGenerationStamp(b.generationStamp);
  
      if (blockId < b.blockId) {
        return -1;
      } else if (blockId == b.blockId) {
        return GenerationStamp.compare(generationStamp, b.generationStamp);
      } else {
        return 1;
      }
    }
docs: {@inheritDoc}