How to compile and extract the packages with classes in a java maven module

Question

I have been trying to create a custom MavenPlugin to extract packages and classes of the current Project.

Here is my code so far:

@Parameter(defaultValue = "${project}")
MavenProject project;


public void execute() throws MojoExecutionException, MojoFailureException {

    File projectBaseDirectory = project.getBasedir(); 
     //Todo?

}