Generation of JAXB based WebService Client(Stub) from WSDL

I found a tutorial using CXF to do what you are looking to here.

That document claims to be using a contract first approach, but it isn't exactly. When discussing SOAP-based services, contract first means creating the descriptors (WSDL, XSD) first. You then generate any code artifacts from those descriptors. You can see the comments in the original blog post for the debate about the original author's choice of words.

That being said, a contract first approach has many benefits depending on what you are trying to accomplish. See the Spring Web Services tutorial for some information about it.

I finally found the answer to this problem.

Despite firewall rules seems correct, the fact that openvpn were listening on a different host (public ip) than apache was the problem. Using same host (and public ip) for openvpn and apache solved it.