Apache has released an application server called Geronimo. There are many open source application servers, so what is special with Geronimo? The answer is that Geronimo can be configured easily to suit your application needs. Typically an application server contains different containers that specifically do a particular job. For example an EJB container will be responsible for EJB related requests and there could be a transaction container that is responsible for handling all the transactions. In most of the application servers these come by default and whether your application uses it or not some of them run by default. This could be an unnecessary consumption of memory and server startup time.

Geronimo’s componentized application server model can be configured to run only the containers that are required for your application. The building block of Geronimo is what is called as GBeans (Geronimo Beans). GBeans are objects that are responsible for handling specific task within the application server. Geronimo extensively uses Dependency Injection pattern, also called Inversion of Control (IoC) pattern (if you want to know more about IoC pattern an excellent starting point would be Martin Fowler’s article on “Inversion of Control Containers and the Dependency Injection pattern“) wherein a container helps in adding the individual services to the kernel and the kernel does not need to know what services it has to run when it starts.  OnJava.com has published recently an article “What is Geronimo?” that introduces Geronimo with instructions to deploy a simple application.