问题
HashedWheelTimers are based on this 1987 paper about how traditional timers consume O(N) processing to maintain (for N timers), but hashed wheels can consume O(1). I'm unsure if Quartz's job scheduling just managers timers underneath, or actually uses an O(1) solution under the covers.
回答1:
The Quartz scheduler is designed for scheduling persistent jobs. So, when Quartz comes up after going down, it can see what jobs were supposed to run but didn't and optionally run th em.
HashedWheelTimer is designed to scale to thousands of timers. They're solving two very different problems.
来源：https://stackoverflow.com/questions/15347600/which-is-more-efficient-nettys-hashedwheeltimer-or-quartzs-scheduler