If you want to make the development with Jease even more easier, you should definetively check out the wonderful JRebel-Product developed by Zeroturnaround (30-days evaluation version available).

With JRebel installed, you can simply modify your Java-code in your IDE and Tomcat will pick up the changes immediatley. This way you don't have to stop/start Tomcat everytime you make any changes to your code.

You will get used to the comfort provided by JRebel very fast and don't want to work without it anymore.

Please note: if you change/add/remove any of the persistent fields of your content-types (= domain classes), you have to restart the application server, so db4o can pick up the changes. This is no limitation of JRebel, it's just how the way db4o works which inspects class-definitions only once while running. In practice this need for a restart is so rare that it is negligible.