[xwiki-users] Registering components

Having been put off writing Java components a number of times I've decided to really tackle the problem head on. I would greatly appreciate any help in this. I've been following the advice in http://platform.xwiki.org/xwiki/bin/view/DevGuide/WritingComponents and I have compiled a Jar identical to the Hello World example except that the class and method names differ, hopefully consistently. I've placed the jar in XE_WAR_HOME/WEB-INF/lib and written a page, which consists only of {{velocity}} $services.mycomponent.greet() {{/velocity}} The output when viewed is simple "$services.alertdb.greet()", so nothing seems to have happened. However, if I restart Tomcat (and then wait a minute or so for XWiki to restart) the output is "Hello", as desired. So is a restart of Tomcat always required? This wasn't mentioned in the guide. And since extensions can be added via the extension manager without a restart, is there a sneaky trick to doing the same with my own components. Also, is a restart necessary when I update the Jar, either with fixed methods or modified interface?