thread mutex

mutex

mutex 就是一种不支持 wait&notify 的 monitor

class Mutex : public Monitor {
    bool notify ()    { ShouldNotReachHere(); return false; }
    bool notify_all() { ShouldNotReachHere(); return false; }
    bool wait (bool no_safepoint_check, long timeout, bool as_suspend_equivalent) {
        ShouldNotReachHere() ;
        return false ;
    }
};