Simple project that has a couple of Javadoc'd classes and Maven plugins configured to automatically generate Javadoc.
Currently, you can generate javadoc with this project by running the javadoc:javadoc goal as follows:
mvn clean javadoc:javadoc
If you really wanted to, you could add a bit more to the pom and you'd wind up with your Javadoc at an earlier stage in the Maven lifecycle. Take the code in the following profile as an example:
mvn clean compile -Pcompile-javadoc
Not only does this profile compile the source, but it attaches the javadoc goal in the javadoc plugin to the compile phase in the Maven lifecycle.