[xxs]

I guess there are extremely few people in the topic who understand how NPE works internally.

There is no null check in the generated assembly code, when a null dereference occurs - it's an effective kernel trap (as 0 is not mapped to the process). The latter uses the code execution pointer to understand what has been attempted to execute and throws the exception. This may or may not involve stack crawl (which is very expensive) depending on JIT ability to prove if the stack would be unused.

Nulls should be avoided, all fields should be initialized, etc. Nulls are great for =very= high performance code as null checks are virtually free.