This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Portlets in Action requires that you have experience in web application development using JSPs and Servlets.
The technologies covered in the book, like Spring, Hibernate are introduced gently to the readers. So, you'll be good even if you don't know Spring/Hibernate.