Can maven projects have multiple parents?

Question

Hi,

we have java and flex projects at work. We currently have 1 base pom that contains the configurations we want to use for both projects. Problem with this is: flex projects inherit configuration for javadoc and pmd for example, which they do not want.

I want to do this a bit more clean and have a real base-pom and then a java-base-pom and a flex-base-pom. But how does this work in a multimodule that has both a flex part and a java part?

We have plugins to our own application where we use the following structure:

• my-plugin
  • my-plugin-client (flex)
  • my-plugin-server (java)

The my-plugin just contains a pom.xml with section. I would use the my-plugin pom.xml as a parent to both, but then I cannot also use the java base-pom or the flex base-pom also as parent. What would be the best approarch for this?

regards,

Wim

Answer 1

Just image that pom.xml are in fact Java classes: you can have only one parent (or extends a class), but this parent can also have another parent, and so on.

As I explained here, you must distinguish the parent and aggregation principles in Maven, which means that my-plugin would be considered as an aggregation project, not necessarily a parent project for both my-plugin-client and my-plugin-parent.

So to summarize:

my-plugin will define the base pom for all your projects. Then, you create two new pom projects: java-base-pom and flex-base-pom. They have both my-plugin as parent. Now, my-plugin-client will have java-base-pom as parent, while my-plugin-server will use flex-base-pom for his parent.

This way, my-plugin-client will inherit all properties defined in the my-plugin pom.xml, and also from java-base-pom project.

Answer 2

The only way is to have base-pom as parent of java-base-pom and flex-base-pom.

I have similar structure for my spring projects:

base-pom (basic configuration - eclipse, reports, repositories, etc)
|
+ spring-base-pom (spring definitions)
  |
  + spring-jar-base-pom (jar specific definitions)
  |
  + spring-war-base-pom (spring web and servlet dependencies)
    |
    + spring-webapp-base_pom (spring web mvc dependencies)