Chapter 5. Singleton Bean, Validations, and SOAP Web Services

Now that we saw how to expose and consume web services using REST, let's see how to use another popular technology, SOAP, to achieve the same results.

Note

There's a wide (and sometimes wild) discussion about which one is better, and we aren't endorsing any of them by setting this specific order—the architectural factors and implications of such decisions are out of scope of this book.

Also, we already accessed the persistence layer provided by the server to connect and retrieve information from a database. In this chapter we will use this mechanism to insert data, detailing the transactional aspects involved, and will declare the bean validation rules to check the values being passed to the database.

Some of these functionalities will be encapsulated by a singleton bean, another new feature of Java EE 6 that makes the developer's life easier but brings a few details that must be considered to achieve the expected results.