Geronimo consists of a set of core features and services as well as a number of critical services provided by other open source products. This is a list of many of those related projects.
The EJB container used by Geronimo
One of the available web containers for Geronimo
One of the available web containers for Geronimo
The JMS provider used by Geronimo
Provides database connection pool adapters in Geronimo, as well as the EJB CMP engine
Provides transaction logging and recovery for Geronimo
These are a selection of the projects that Geronimo depends upon.
Web Services features
Bytecode manipulation library
Utility classes for concurrency
http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html
Embedded database
A number of separate libraries offering common utility functions
The JMX engine that Geronimo is built on
Used by several included web applications (debug console, etc.), as well as the Geronimo build and packaging process
XML binding library used to read and write deployment descriptors and configuration files