Question

Is there a way to change the version number without editing the POM?

<groupId>org.example</groupId>
<artifactId>example</artifactId>
<version>1.0.0</version>

We have a CI system where we want to release nightly builds, but without using the -SNAPSHOT solution of Maven, so if 1.0.0 is the current version, we just want to have CI-NIGHTLY-BIULD-20120426.

I suggested this would be possible with something like mvn deploy -Dversion=CI-NIGHTLY-BIULD-20120426, but obviously not. The bad solution would be to let the CI server edit the pom.xml every time, but I think this is very unhandy.

Thank you!

Answer 1

I suggest to use classifier.

<groupId>foo</groupId>
<artifactId>bar</artifactId>
<version>1.0</version>

<properties>
    <!-- default classifier is empty -->
    <my.project.classifier></my.project.classifier>
</properties>

<build>
...
<plugins>
  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-jar-plugin</artifactId>
    <version>2.3.1</version>
    <configuration>
      <classifier>${my.project.classifier}</classifier>
    </configuration>
    <executions>...</executions>
  </plugin>
</plugins>
</build>

and

mvn package -Dmy.project.classifier=NIGHTLY-2012-04-26_02-30

---

Maven documentation says about classifier:

classifier: You may occasionally find a fifth element on the
coordinate, and that is the classifier. We will visit the classifier
later, but for now it suffices to know that those kinds of projects
are displayed as groupId:artifactId:packaging:classifier:version.

and

The classifier allows to distinguish artifacts that were built from
the same POM but differ in their content. It is some optional and
arbitrary string that – if present – is appended to the artifact name
just after the version number. As a motivation for this element,
consider for example a project that offers an artifact targeting JRE
1.5 but at the same time also an artifact that still supports JRE 1.4. The first artifact could be equipped with the classifier jdk15 and the
second one with jdk14 such that clients can choose which one to use.

Another common use case for classifiers is the need to attach
secondary artifacts to the project’s main artifact. If you browse the
Maven central repository, you will notice that the classifiers sources
and javadoc are used to deploy the project source code and API docs
along with the packaged class files.