What's the difference between PoolTcpConnector and SimpleTcpConnector ?
The simple connector hasn't been designed to be used unless you know that you will process only a request at a time.
You can use it, for example, if you are running Tomcat under Apache, using mod_jk. In that case Apache talks with tomcat using the Apj13 protocol, and you need only one connector listening with the Ajp12 protocol for shutting down Tomcat. In that case using a pool would be a waste of resources.