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Modules should be independent of the runtime container.
Modules with excessive runtime container dependencies are heavyweight modules that cannot execute outside the confines of the runtime container. A good example of a heavyweight technology is Enterprise JavaBeans (EJB), and the meteoric rise in popularity of lighter-weight frameworks, such as Spring, are the direct result of the shortcomings of heavyweight technologies. While lightweight modules are not container dependent, they are still able to leverage the infrastructure capabilities (e.g., security, transactions) of the container. Lightweight modules with no container dependencies have two significant advantages.
weight and granularity, 63