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Let's say I want to install project-local dependencies (jar files) to my local maven repository (~/.m2) prior to compiling the project so I can reference them in my POM just like I would reference any dependency from Maven Central. Currently, I'm using Maven install plugin's install-file goal attached to the 'clean' phase (because my IDE uses it), like so:

<dependencies>
   <dependency>
      <groupId>group.id</groupId>
      <artifactId>artifact.id</artifactId>
      <version>artifact.version</version>
   </dependency>
</dependencies>

<build>
   <plugins>
      <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-install-plugin</artifactId>
         <version>2.5.2</version>
         <executions>
            <execution>
               <id>install-my-local-dependency</id>
               <phase>clean</phase>
               <goals>
                  <goal>install-file</goal>
               </goals>
               <configuration>
                  <groupId>group.id</groupId>
                  <artifactId>artifact.id</artifactId>
                  <version>artifact.version</version>
                  <file>${project.basedir}/lib/local-dep.jar</file>
                  <packaging>jar</packaging>
                  <generatePom>true</generatePom>
               </configuration>
            </execution>
         </executions>
      </plugin>
   </plugins>
</build>

When I execute mvn clean (or its equivalent in the IDE), everything runs as I'd expect:

--- maven-clean-plugin:2.5:clean (default-clean) @ MyProject ---

--- maven-install-plugin:2.5.2:install-file (install-...) @ MyProject --- Installing ${project.basedir}/lib/local-dep.jar to ~/.m2/repository/group.id/artifact.id/local-dep.jar

But when I execute mvn clean install instead (or its equivalent in the IDE), I get the following error:

Failed to execute goal on project MyProject: Could not resolve dependencies for project com.example.MyProject:jar:1.0: Could not find artifact group.id:artifact.id:jar:artifact.version in central (https://repo.maven.apache.org/maven2) -> [Help 1]

For some reason, Maven install plugin's install-file goal either does not run in this case, or doesn't run soon enough. Why? The other StackOverflow answers I found explain differences between both commands but in my eyes, they do not explain this particular difference as my project has no modules.

Is there a better way of doing the same thing cross-platform, even on build servers (e.g. Jenkins) and with at least one other dependent project?

Should it be any help, I have the following Maven versions:

  • CLI: 3.6.0
  • IDE: 3.3.9
J. Smolik
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  • How can you install the artifact without compiling it ? If your dependency is coded as per your question then it will never work, as no such artifact exists anywhere. Your local repo is supposed to contain built artifacts – jr593 Aug 12 '19 at 10:01
  • Check this https://stackoverflow.com/questions/6018701/how-is-mvn-clean-install-different-from-mvn-install – Null Pointer Aug 12 '19 at 10:30

1 Answers1

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Maven first analyses the pom.xml and then calls the goals/phases. The analysis itself is complicated and has different depths, so I guess that calling clean alone will not make Maven analyse the dependencies, but calling clean install does so. Note that the analysis of the POM only happens once, not again for every goal/phase.

Generally, your approach cannot be recommended. Usually, you put project dependencies into remote Maven repositories, so that they can be resolved through them. If you work inside a company, you should set up a Nexus/Artifactory server that handles your artifacts.

If you want people outside your company to build the artifact, you need to find a provider for Maven repositories. I guess that github/gitlab can help you here. Then you need to add those repositories to the POM.

J Fabian Meier
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