Embedded servlet containers

In previous radars we have talked about embedded servlet containers, and these are now widely adopted on our projects. Tools such as SimpleWeb and Webbit take the simple, embedded approach further and offer raw HTTP server functionality without implementing the Java Servlet specification. At the same time, Tomcat, the most popular Java application server, is increasingly used in embedded setups and Microsoft provides self-hosted servers for the .NET framework, lending further weight to this Trend.

We have talked much already about embedded servlet containers - and these are now widely adopted on our projects. Tools such as SimpleWeb and Webbit take the simple, embedded approach further and offer raw HTTP server functionality without implementing the Java Servlet specification. We are pleased to see a corresponding reduction in the complexity of test code that takes advantage of this.

Embedding a servlet container, such as Jetty, inside a Java application has many advantages over running the application inside a container. Testing is relatively painless because of the simple startup, and the development environment is closer to production. Nasty surprises like mismatched versions of libraries or drivers are eliminated by not sharing across multiple applications. While you will have to manage and monitor multiple Java Virtual Machines in production using this model, we feel the advantages offered by the simplicity and isolation are significant.