Maven generating two jar files when used with "classifier" tag

build, java, maven

Solution

Looking at the documentation it seems that classifier is used to generate additional jars.

See here:

Specify a list of fileset patterns to be included or excluded by adding / or / and add a classifier in your pom.xml.

Note: the jar-plugin must be defined in a new execution, otherwise it will replace the default use of the jar-plugin instead of adding a second artifact. The classifier is also required to create more than one artifact.

So, as per document it sounds as if you do not provide `<id>` to execution it will overwrite the default jar mechanism and give you a single jar with `-gc.jar` appendix. But it does not. You always end up with two jars.

I have hacked it a bit, you can just override the default settings by using default plug-in id. So, here is what gives me single jar with `-gc.jar` name.

<build>
  <plugins>
    ...
    <plugin>
        <artifactId>maven-jar-plugin</artifactId>
        <executions>
            <execution>
                <id>default-jar</id>
                <phase>package</phase>
                <goals>
                    <goal>jar</goal>
                </goals>
                <configuration>
                    <classifier>gc</classifier>
                </configuration>
            </execution>
        </executions>
    </plugin>
  </plugins>  
</build>

Problem

Original source