Azure Websites also support Java, executed through Tomcat or Jetty (two open source Web servers and Servlet containers). An in-depth discussion of Java language and platform is out of the scope of this book. So, in this recipe, we are going to look at the two supported runtimes.

Tomcat and Jetty's heritage is about 20 years old and they have become the leading platform for web applications written in Java. They are called Servlet container because they implement only the Servlet specification. A Servlet is a Java class that can respond to clients' requests, mostly used to respond to HTTP requests. The Java Servlet specification is part of the Java EE platform. However, both Tomcat and Jetty don't implement the full Java EE stack, as they are only Servlet container.

On the other hand, there are huge projects such as GlassFish or JBoss implementing the full Java EE stack, which includes JSF (Java Server Faces), EJB (Enterprise Java Beans), JTA (Java Transaction...