How can I systematically determine which jars I'll need, and thus should include in my pom.xml file (I'm using maven as my project management tool)?

When learning spring, to keep things simple, added all the jars (even the ones I never used) to the classpath.

Right now for the most part, I'm guessing which jars to include. For example, I know in my spring configuration file, I have:

<tx:annotation-driven />
<context:annotation-config />
<aop:aspectj-autoproxy />

So, I guess I'll need: spring-context-x.x.x.jar, spring-tx-x.x.x.jar, spring-aop-x.x.x.jar

Thanks.