Can't use classes from different Maven modules

Your parent pom has packaging type pom, this is not jar. This is special aggregator module. All java code should be located in jar modules.

Module with packaging type pom cant generate artifacts like jar, war or ear.

Maven by Example - The Simple Parent Project

The parent project doesn’t create a JAR or a WAR like our previous projects; instead, it is simply a POM that refers to other Maven projects.

To use Classes from one module in other module use maven dependency.

Typical project looks like this:

* administration project (pom)
   * registration (jar)
   * portal (war)