This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
Ehm..yes? "save memory and satisfy other non functional requirement" is far to vague a goal to say for sure, and largely memory and whatever other non-functional requirements you define can be met more based on how you implement your application, not what you implement it with.