I'm a beginner at Maven and I've played with it from a command line point of view a little, so now I was trying to use it in Eclipse; I installed the m2eclipse plugin to do so.
But I'm stumped from the very beginning! Apparently I've missed a bit of terminology somewhere along the line. I can't keep track of all these new Maven terms... What is a Maven Project, and what is a Maven Module? These are my options when creating a new project in the Maven category in Eclipse.
They are basically the same thing, but with one difference. When you create a module, you must specify a parent project. When you specify the parent project, it adds a <modules> section to the parent projects pom.xml. That section basically says to the parent project, "run every command I get against all of my modules first". So if you run, "mvn package" on the top level project, it will run "mvn package" against all it's module projects first.
Hope that helps.
Found it! My searches were returning tons of hits for creating a "multi-module project", but once I added "-multi" to my query, the answer was on the first page.
According to Creating and Importing Projects:
m2eclipse provides the ability to create a Maven module. Creating a Maven module is almost identical to creating a Maven project as it also creates a new Maven project using a Maven archetype. However, a Maven module is a subproject of another Maven project typically known as a parent project.
来源：https://stackoverflow.com/questions/2890341/maven-module-vs-project-eclipse-m2eclipse-plugin