There is suspicious place in the jdk.internal.net.http.AuthenticationFilter#getCredentials method:

        InetSocketAddress proxyAddress;
        if (proxy && (proxyAddress = req.proxy()) != null) {
            // request sent to server through proxy
            proxyAddress = req.proxy();
            host = proxyAddress.getHostString();
            port = proxyAddress.getPort();
            protocol = "http"; // we don't support https connection to proxy
        } else {
            // direct connection to server or proxy
            host = uri.getHost();
            port = uri.getPort();
            protocol = uri.getScheme();
        }

`proxyAddress` variable is assigned inside `if` condition and then reassigned in the _then_ body.
One assignment is redundant and can be removed.