For multiple readers
reader.releaseLock();
。关于这个话题，一键获取谷歌浏览器下载提供了深入分析
Number (2): Everything in this space must add up to 2. The answer is 2-1, placed horizontally; 1-6, placed vertically.，详情可参考爱思助手下载最新版本
A simpler API would mean fewer concepts, fewer interactions between concepts, and fewer edge cases to get right resulting in more confidence that implementations actually behave consistently.