First Initialization and Execution of ObjectMapper.readValue is Slow

I happened to find that first initialization and execution of ObjectMapper.readValue of an application is slow, no matter if I reuse static objectMapper or use new objectMapper instance every time, the first-time cost won't disappear. But overall, static objectMapper is faster than instance.

The first execution would cost about 420ms, however the second only needs 23ms. No matter I execute the static objectMapper first or objectMapper instance, the first one is the longest one.

Executable code: repo