The quick summary of the question and its resolution:
My use case involved a request to a server whose response back was a 302 redirect using non-persistence on the connection.
The current implementation of the HttpClient on version 4.4.1 GA will implicitly launch a follow-up request to the path specified in the "location" header path from the 302 response. The problem is, when the httpclient is sent with the "Connection: close" header, it is not aware of having done so. The result is that, if the server responds WITHOUT a corresponding "Connection: close", the client will assume the connection must be kept alive, and perform the next request for the redirect path on the same connection. This obviously leads to a problem since the server will have closed the socket on its end of the connection by now.
The problem was ultimately fixed by forcing the server to send a "Connection: close" header in response to the HttpClient's "Connection:close". However, according to the HTTP 1.1 spec, the server is not obliged to do this, although, it should. http://tools.ietf.org/html/rfc2616#section-8:
However, on the client side, the rules on the matter are stricter.
Ideally, there should be a way for the HttpClient to realize it has announced its intention to close the connection via the "Connection: close" header, and stop itself from sending any more requests on the connection, without outside intervention from the server it's communicating with.
This issue was not observed in HttpClient 4.2.6