The activities become loosely coupled, (i.e. do not run within the same technology or call stack, under the same security authority, with a dedicatedconnection between them).
It is the preferred mode to use from dedicated workstations with a high-speed network connection to the mail server.
对于通过高速网络连接访问邮件服务器的专用工作站来说,这种模式是首选模式。
3
In the classic servlet model, an open connection means a dedicated thread is doing nothing but waiting until it needs to update the client in response to an event.