The project I'm currently working on (intranet web application) mainly uses Tomcat, Spring, Freemarker, XSLT and FOP and as a result any new side projects (all intranet web apps) I implement using the same technologies. I want to expand my horizons but with so many options I'm not sure what to dedicate my study time to next. I thinking of the following:
I'm sure there are plenty of others that I'm not even aware of. What would you recommend for the following areas for market coverage (if I was to change jobs) or simply because it's the best tools for the job (I know this is very objective)?
Databases are used in almost every project. I think learning JPA and Hibernate would be a good idea. JPA (Java Persisence API) is a standard interface for object-relational mapping (mapping from Java objects to rows in tables in a relational database). Hibernate is an implementation of JPA.