generating client form WSDL: https://db-blog.web.cern.ch/blog/luis-rodriguez-fernandez/2014-07-java-soap-client-certificate-authentication
certificate setup:
- store the .pfx file under src/main/resources/
- edit src/main/resources/clientKeystore.properties
- configure the .pfx file name
- configure the password
- configure the certificate/key alias
- edit src/main/java/example/PasswordCallbackHandler.java and set the same password
example of invoking service method(s): src/main/java/example/ExampleCXF.java