Quick Recap of J2EE

As can be seen here, a request for getting a jsp first reaches a web-server (e.g. apache). Apache checks up its virtualhost for the specified URL, identifies the document root, picks up the JSP, and then Apache then hands over the request via module mod_jk to Tomcat, whose job it is to do the following 

One can even look upon the processing as follows (taken from Wikipedia)

If one is looking at things from the J2EE model, one typically works with a MVC relationship between classes - the relationship works as follows (ill put up a picture on this soon).

Software Engineering

Making a list of some software engineering concepts and principles ive come across.

• Decorator (wrapper where API of object being used is same as exposed)
• Adaptor (wrapper but where API of object being used is different from exposed API)
• Singleton (static object, private constructor)
• Factory (when e.g. one needs to create an Matrix of different types based on the type specified in the constructor e.g.). See this 
• Inversion of control e.g. the same example i described above for factory can be better implemented when each Matrix type is implementing an interface (or extending virtual classes) and when the factory class's constructor is created, the concrete object is passed, and then appropriate functions can be called). See this
• Definition of "static" keyword in C++: this keyword has 3 uses. limit scope within translation unit, retain value across function calls, do not be part of object instances