The MulitValueMap size does't increase when used put(K key, List value) in LinkedMultiValueMap?

Question

I have a text string to read,and I want to put it to MultiValueMap,

123   2020-8-3 09:00:00 4.4 5.5 6.6
124   2020-8-3 09:00:00 5.5 6.6 4.4
125   2020-8-3 09:00:0