The SCJD does not require you to use a
servlet container, like Tomcat. In fact, the SCJD really has nothing to do with servlet or web application development - that would be the web component developer, or SCWCD, exam. Perhaps that's what you're interested in doing(?) The SCJD is concerned with measuring your ability in developing applications using the
Java 2 Standard Edition (J2SE). Basically, you are required to develop your own cleint/server application, including GUI and database access. In short, there's no use for Tomcat anywhere really.
Rich