How to activate a Maven profile in a dependent module?

Question

Suppose I have a module A:jar, whose runtime and compilation set of dependencies depends on the JDK version. In my example, I have a pre-jdk6-profile

Answer 1

a) In a multi-module build, you should always build from the top pom, never from an individual module. If you want to build only one module, use advanced reactor options (see mvn --help) like this:

mvn -pl mymodule

b) Define and activate the profile in the parent pom, but add the configuration in the child pom.

parent pom.xml

<profiles>
    <profile>
         <id>pre-jdk-6</id>
         <activation>
            <jdk>(,1.6.0)</jdk>
         </activation>
    </profile>
</profiles>

child pom.xml

<profiles>
    <profile>
        <id>pre-jdk-6</id>

        <dependencies>
            <dependency>
                <groupId>javax.xml.ws</groupId>
                <artifactId>jaxws-api</artifactId>
            </dependency>
        </dependencies>
    </profile>
</profiles>

Answer 2

Several notes way after the fact:

1. When you use -P profName, it activates a profile named 'profName'
2. After that, it disables all profiles that have an <activation> tag for them. It doesn't matter whether they are activated by the java version, as in the example, or by default or env value or anything.
3. That means the -P causes any otherwise activated profile to become deactivated.

Solution: Either use <activation><jdk>...</jdk></activation> or use -P but do not use both.