Why jucCopyOnWriteArrayList creates a local lock variable inside methods

Question

I recently checked the jucCopyOnWriteArrayList implementation in OpenJDK sources and found that the lock variable defined inside the class is updated with the following statement

final ReentrantLock lock = this.lock;

inside all methods requiring this variable. Any specific reason for such a reevaluation of a variable (which may conceal a global variable). You cannot directly use the "lock" field of an object.

Answer 1

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