Mutability Key to Imperative Logic

The only reason imperative logic (a.k.a instructions) execute in sequence is that due to the presence of mutable stored values, the result is dependent on the evaluation order. Using your vocabulary, an "instruction" can (and a "rule" cannot) operate on mutable values. – Shelby Moore III

http://stackoverflow.com/questions/602444/what-is-functional-declarative-and-imperative-programming

Separating Programming from Presentation

"In other words, Velocity doesn't remove programming from presenation; rather it requires users to learn a new ad hoc scripting language. By requiring Web page designers to learn the Velocity Template Language, Velocity fails to eliminate the mingling of the content and presentation." http://www.learningace.com/doc/5903174/2b2d80be66064d5c810bebcd444b927c/j-jsptags

Maven - the "Convention over Configuration" Disadvantage

The Maven approach reduces the JAR-file bloat that consumed most version-control repositories. But using Maven encourages you to adopt its "convention over configuration" approach to building software, which can limit your flexibility in customizing your build scripts.

http://www.ibm.com/developerworks/java/library/j-ap05068/