In Using JNDI binding for constants from the server configuration files you can read about defining JNDI bindings for constants in WebSphere Application Server 8.5 Liberty Profile (aka WebSphere Liberty Profile, Liberty Profile or simply Liberty). I was surprised to have read about the feature without a code with the @Resource annotation.
I sat down and wrote a document to get you started with the Liberty Profile and JNDI with @Resource annotation. It’s very short, simple and should suit your time constraints. Give the document Using @Resource to access JNDI in WebSphere AS 8.5 Liberty Profile a read and let me know your thoughts.