Secure Webcocket Tomcat

I am having problems with WebSocket connection over TLS on Tomcat 8.

I have installed the following connectors:

<Connector  port="8080" protocol="HTTP/1.1"
            connectionTimeout="20000"
            redirectPort="8443"
/>

<Connector  port="8443" protocol="org.apache.coyote.http11.Http11NioProtocol"
            maxThreads="150" SSLEnabled="true" scheme="https" secure="true"
            clientAuth="false" sslProtocol="TLS"
            keystorefile="${user.home}/.keystore" keystorePass="password"
/>

      

        
        
        
      

    

Inside a standard Tomcat servlet named "socket", I used the @ServerEndpoint annotation on the class to create a WebSocket endpoint. So the abbreviated version looks like this:

@ServerEndpoint(value = "/echo")
public class EchoServer {
    @OnOpen
    public void onOpen(Session session) {
        //
    }

    @OnMessage
    public void onMessage(String message, Session session) {
        //
    }

    @OnClose
    public void onClose(Session session) {
        //
    }
}

      

        
        
        
      

    

On my client side, I have a html script connecting a WebSocket:

var webSocket = new WebSocket("ws://localhost:8080/socket/echo");

      

        
        
        
      

    

When I connect to http: // localhost: 8080 / socket everything works fine. I can open a socket connection and send messages back and forth.

Using https: // localhost: 8443 / socket I can connect to the servlet, but I cannot open a socket connection as it is an unsafe operation. Then I tried to change the connection string to:

var webSocket = new WebSocket("wss://localhost:8443/socket/echo");

      

        
        
        
      

    

but i cant get any connection.

When I look at the Tomcat docs ( https://tomcat.apache.org/tomcat-8.0-doc/web-socket-howto.html ) I don't understand what I need to change - I see mention of SSL_CONTEXT and the like, but I can't find any example of how this is used (I don't have a ClientEndpointConfig, since is it a browser?).

Can anyone point me to a solution? Why is a connection that works fine on the http port not working on the https port?