KryoSerializer is more space consuming than JDKSerializer?

[a1364533187]

In class KryoSerializer, I see the comments about SerializeUtil with Kryo, which is faster and more space consuming., but when I read this article https://www.shenyanchao.cn/blog/2019/02/13/redis-serializer/, it looks like KryoSerializer is faster and less space consuming.

article reference: https://www.shenyanchao.cn/blog/2019/02/13/redis-serializer/