Right now we are running into a problem where we have a bunch of "open TCP connections" on our Windows server's that are running a tomcat webserver. The Java code is doing a SOAP call to a vendor, and we see a lot of open connections in Resource Monitor (pictured below) showing the vendor's IP address. I've tried a couple different methods of doing the SOAP call thinking the connection wasn't explicitly being closed somewhere behind the scenes. Nothing has worked so far, so I'm thinking that I may be misunderstanding what this page is actually showing.
What is the lifecycle for a TCP connection as it relates to the Windows Resource Monitor? Is it normal for connections that are no longer being used to stay out there for a while? If not, how do I remedy the situation?
It'll be either a connection pool or a resource leak in your code.
To make sure it's not a resource leak check your code to make sure that whatever object is making the network call closes the connection after it's used otherwise you'll be waiting until the garbage collector runs.
However, if the network client supports connection pooling then closing it may only place the open connection back into a pool ready for quick re-use. You don't say which client API you're using but if it supports pooling then it should provide an API to say how long released connections remain in the pool.
There is no Windows Winsock-level pooling or persistence. If the underlying socket gets closed then that's it, it gets closed.