We have a Servlet Filter that calls a different HTTP service. After the call has returned, the target service leaves the connection open/alive for other requests to follow. After some timeout, the target service closes the connection. Normally, a client service confirms that the connection is closed, but in this case it does not, so it stays in CLOSE-WAIT.

This only happens, if we use it from within the Servlet Filter and use the JEE or MP APIs.

We had a live incident, because the possible number of open sockets was exceeded, so our service couldn't open new connections.