Difference between --also-make and --also-make-dependents

Question

I recently learned about --also-make parameter that you can pass to Maven. From what I understand it causes that not only my-project will be build but also all projects dependent to my-project.

mvn --projects my-project --also-make install

But there is also another parameter called --also-make-dependents. From description it looks like it does the same thing as --also-make, but my friend at work told me that they are not the same thing. What is the difference?

Answer 1

• --also-make builds all projects that my-project depends on
• --also-make-dependents builds all projects that depend on my-project

If you imagine DAG (Directed Acyclic Graph) of dependencies between projects (where edge A -> B means that B is dependent on A), then --also-make builds all projects from project my-project towards the "root" projects and --also-make-dependents builds all projects from project my-project towards the "leaf" projects.

Example

Let's say you have following projects:

 dao     util
   \     /
  services
     | 
   webapp

Then

mvn --projects services --also-make

will build dao, util and services. And

mvn --projects services --also-make-dependents

will build services and webapp