NOTE
Nonfair ReentrantReadWriteLock
Default read/write-lock acquisition, reader/writer barging policy, writer-starvation avoidance heuristics, and throughput trade-offs.
This is a historical learning note and may contain outdated or incomplete understanding.
1. Nonfair Does Not Mean Readers Always Win
The default read/write lock allows more opportunistic acquisition than fair mode, but implementations still include policy to avoid pathological writer starvation.
2. Throughput
Allowing currently running threads to acquire when safe can reduce context switches and increase throughput.
3. Starvation/Fairness
Observed fairness is weaker than fair mode. If a workload has strict latency/fairness requirements, test fair mode or choose a different concurrency design.
4. Version-Sensitive Internals
Historical JDK 8 source explanations are useful for learning AQS shared/exclusive mechanics, but exact reader-blocking heuristics and fields should be checked against the actual JDK source in use.