Tag Archives: maven

Maven version contains expression but should be a constant

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In the following example Maven 3 will output a warning Maven version contains expression but should be a constant. This is because we use the expression ${project.parent.version} in the version tag of this Maven module.

<parent>
   <groupId>com.mycompany</groupId>
   <artifactId>myapp</artifactId>
   <version>5.0.0-SNAPSHOT</version>
</parent>

<groupId>com.mycompany</groupId>
<artifactId>myAppEar</artifactId>
<version>${project.parent.version}</version>

So why is Maven complaining about Maven version contains an expression ?

Maven version contains an expression It doesn’t make much sense to make this version non-static, because the maven-release-plugin will automatically update it when doing a release. (eg. when it will change). Make the pom.xml the master of the version tag, not some other file; this will make your life easier when you start eg. using the maven-release-plugin (no need for special configuration)

If you want to use the parent pom version in sub-modules, you can remove it, because the sub-module will automatically inherit the version of the parent if it is ommitted.