The above is fine (as I said in comment) unless your WSDL is accessible with https:// too.
Here is my workaround for this:
Set you SSLSocketFactory as default:
HttpsURLConnection.setDefaultSSLSocketFactory(...);
For Apache CXF which I use you need also add these lines to your config:
<http-conf:conduit name="*.http-conduit">
<http-conf:tlsClientParameters useHttpsURLConnectionDefaultSslSocketFactory="true" />
<http-conf:conduit>