WildFly 11 recently started using the new JChannel(Protocol...) constructor for creating channels. This has resulted in the inability to configure certain protocol properties, most notably, initial_hosts for TCPPING.

Because this constructor calls resolveAndAssignFields(...) with an empty map, if a property was explicitly set, and its associated system property does not exist, and that property uses a non-default converter, then it will have its value undefined (or, more specifically, set to whatever the converter does with a null value).

Additionally, if the assocated system property did exist, it would take precedence over an explicitly set value. I don't think that's a good idea.

Consider the following:

        TCP transport = new TCP();
        transport.setBindAddress(InetAddress.getLocalHost());
        transport.setBindPort(9600);
        TCPPING ping = new TCPPING();
        ping.setInitialHosts(Collections.singletonList(new IpAddress(transport.getBindAddress(), transport.getBindPort())));
        JChannel channel = new JChannel(transport, ping);

        assert !ping.getInitialHosts().isEmpty() : "No initial hosts!";

Side note: new JChannel(Collection<Protocol>) should really be new JChannel(List<Protocol>), since the collection should be ordered.