In Chapter 14, you learned a bit about how JAX-RS fits in the grander scheme of things like Java EE and Spring. In this chapter, there are two similar examples that define the services illustrated in Chapter 2. The first marries JAX-RS with EJB. The second uses Spring to write our JAX-RS services. Instead of using in-memory maps like the earlier examples in the workbook, both examples use the Java Persistence API (JPA) to map Java objects to a relational database.