JPA dao layer tuning …Tomcat configuration issues

The issues of persistance have taken the most of my sparetime recently as I have planned the implementation details of JPA entity layer…
good basis for investigation have provided the 2 series of peristance provided by IBM Developerworrks articles..namely

Patterns of persistence, Part 1: Strategies and best practices for modern ORM tools
and Patterns of persistence, Part 2: Increase code reuse and enhance performance,other useful links are oracle’s best Java
Persistance practices article and the JEE blueprints of persistance….