How do I force Maven to use my local repository rather than going out to remote repos to retrieve artifacts?

Dave picture Dave · Nov 5, 2015 · Viewed 193.7k times · Source

I’m using Maven 3.3.3 with Java 8 on Mac Yosemite. I have a multi-module project.

    <modules>
            <module>first-module</module>
            <module>my-module</module>
                …
    </modules>

When I build my one of my child modules, for example, “my-module” from above, using “mvn clean install”, the build attempts to download the child module artifacts from a remote repository I have defined in my ~/.m2/settings.xml file. Output is below

[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building my-module 87.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
Downloading: https://my.remoterepository.com/nexus/content/repositories/snapshots/org/mainco/subco/first-module/87.0.0-SNAPSHOT/maven-metadata.xml
Downloading: http://download.java.net/maven/2/org/mainco/subco/first-module/87.0.0-SNAPSHOT/maven-metadata.xml
Downloaded: https://my.remoterepository.com/nexus/content/repositories/snapshots/org/mainco/subco/first-module/87.0.0-SNAPSHOT/maven-metadata.xml (788 B at 0.9 KB/sec)
Downloading: https://my.remoterepository.com/nexus/content/repositories/snapshots/org/mainco/subco/first-module/87.0.0-SNAPSHOT/first-module-87.0.0-20151104.200545-4.pom

How do I force Maven to check my local ~/.m2/repository first before trying to download from the remote repositories? Below is where I have my remote repositories defined in my ~/.m2/settings.xml file …

<profile>
    <id>releases</id>
    <activation>
        <property>
            <name>!releases.off</name>
        </property>
    </activation>
    <repositories>
        <repository>
            <id>releases</id>
            <url>https://my.remoterepository.com/nexus/content/repositories/releases/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
</profile>
<profile>
    <id>snapshots</id>
    <activation>
        <property>
            <name>!snapshots.off</name>
        </property>
    </activation>
    <repositories>
        <repository>
            <id>snapshots</id>
            <url>https://my.remoterepository.com/nexus/content/repositories/snapshots/</url>
            <releases>
                <enabled>false</enabled>
            </releases>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>
</profile>

Edit: In response to the answer saying that the download occurs when the artifact is not there, below is the terminal output in which I prove the file was there in my repo but Maven is trying to download it anyway ...

Daves-MacBook-Pro-2:my-module davea$ ls -al ~/.m2/repository/org/mainco/subco/first-module/87.0.0-SNAPSHOT/first-module-87.0.0-SNAPSHOT.jar 
-rw-r--r--  1 davea  staff  10171 Nov  5 10:22 /Users/davea/.m2/repository/org/mainco/subco/first-module/87.0.0-SNAPSHOT/first-module-87.0.0-SNAPSHOT.jar
Daves-MacBook-Pro-2:my-module davea$ mvn clean install
[INFO] Scanning for projects...
[WARNING] 
[WARNING] Some problems were encountered while building the effective model for org.mainco.subco:my-module:jar:87.0.0-SNAPSHOT
[WARNING] 'build.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-antrun-plugin @ org.mainco.subco:my-module:[unknown-version], /Users/davea/Documents/sb_workspace/my-module/pom.xml, line 678, column 12
[WARNING] 
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING] 
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING] 
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building my-module 87.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
Downloading: https://my.remoterepository.com/nexus/content/repositories/snapshots/org/mainco/subco/first-module/87.0.0-SNAPSHOT/maven-metadata.xml
Downloading: http://download.java.net/maven/2/org/mainco/subco/first-module/87.0.0-SNAPSHOT/maven-metadata.xml
Downloaded: https://my.remoterepository.com/nexus/content/repositories/snapshots/org/mainco/subco/first-module/87.0.0-SNAPSHOT/maven-metadata.xml (788 B at 0.8 KB/sec)
Downloading: https://my.remoterepository.com/nexus/content/repositories/snapshots/org/mainco/subco/first-module/87.0.0-SNAPSHOT/first-module-87.0.0-20151106.043202-8.pom
Downloaded: https://my.remoterepository.com/nexus/content/repositories/snapshots/org/mainco/subco/first-module/87.0.0-SNAPSHOT/first-   module-87.0.0-20151106.043202-8.pom (3 KB at 21.9 KB/sec)
Downloading: http://download.java.net/maven/2/org/mainco/subco/subco/87.0.0-SNAPSHOT/maven-metadata.xml
Downloading: https://my.remoterepository.com/nexus/content/repositories/snapshots/org/mainco/subco/subco/87.0.0-SNAPSHOT/maven-metadata.xml

Answer

Andreas Veithen picture Andreas Veithen · Nov 7, 2015

The dependency has a snapshot version. For snapshots, Maven will check the local repository and if the artifact found in the local repository is too old, it will attempt to find an updated one in the remote repositories. That is probably what you are seeing.

Note that this behavior is controlled by the updatePolicy directive in the repository configuration (which is daily by default for snapshot repositories).