On Jobspotting, you can browse a limited selection of (3 jobs) in Madrid. The most common categories in this area are at the moment Java and Software Engineering. Read up on areas like Hibernate, Apache Struts, and Jpa to arm yourself with the right knowledge for these job offers.
Companies are at the moment seeking only qualified applicants. There are no startup companies advertising Gwt jobs on Jobspotting at the moment. Why not have a look at job opportunities in another country to compare and contrast opportunities. Just use the Explore tab.