Google App Engine中的单身人士（或更常见的分布式服务器环境）如何运作？

I am intrigued as to how singletons work in Google App Engine (or any distributed server environment). Given your application can be running in multiple processes (on multiple machines) at once, and requests can get routed all off the place, what actually happens under the hood when an app does something like: 'CacheManager.getInstance()'?I am intrigued as to how singletons work in Goo