Free Tools to make your J2EE Development Easier

I've been writing Java and J2EE code for the past 9 years. Over the years I have found a number of free tools to make my life easier. Here is a list of my favorite time saving tools, feel free to add your own.

1. Eclipse - The best Java IDE (I know, Eclipse is more than an IDE, but it is widely used as one.).
2. XDoclet - Automatically generates Home and Remote interfaces, as well as deployment descriptors for EJBs (can also be used to generate deployment descriptors for Hibernate, JDO, Tapestry and many others).
3. Web Tools Project - An Eclipse plugin to facilitate J2EE development, I'm especially fond of the JSP editor.
4. Hibernate - Object Relational Mapping tool.