That's not a straightforward task.
Maven does not work using path-style dependencies, which are what classpaths literally are. Maven's dependencies are all based on a discrete Maven ID (artifactId, groupId and version) which is not directly deducible from the name of the dependency jar or the classpath. In fact, periodically some project or other will make an annoying change about where in the Maven namespace they want to be found and I have to go on a "treasure hunt" to fix things.
The location of Maven dependencies is also very different. In a non-Maven project, the dependency jars are located in one or more designated areas of the project and/or in external directories of unpredictable location (or at least unpredictable if you don't know the classpath, including any ECLIPSE variable substitutions). Maven dependency jars, however, are not kept on a per-project basis, they're fetched on-demand from the Maven cache when building a target and do not otherwise exist in the project.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.