With JAX-RS 2.0 client you can access whatever backend you like--it only has to speak HTTP. So you can use JAX-RS 2.0 client now from Java clients or to drive system tests:
See also other screencasts at: http://tv.adam-bien.com or subscribe to http://www.youtube.com/user/bienadam.
See you at Java EE Workshops at MUC Airport, particularly at: Java EE 7 Bootstrap!
NEW MUC Airport Workshop: Migrating Java Client (Swing / Java FX) to Web Standards
Airport MUC workshops: Web (SPA, PWAs, Offline, Desktop, Mobile) Applications Essentials and Effective Web Applications. No migrations. #usetheplatform
Podcast: airhacks.fm and newsletter: airhacks.news
A book about rethinking Java EE Patterns