Because of his ongoing interest in system-level programming, he eventually worked his way to Sun's R&D Java EE department, later acquired by Oracle, and has been involved with web services development since 2003. At present, Marek is Spec Lead of JSR 339, JAX-RS 2.0: The Java API for RESTful Web Services API, as well as the development lead of Jersey, the next major JAX-RS Reference Implementation release. Previously Marek was leading development on Metro, the open-source SOAP web services framework for Java.