Nexus is not caching maven central plugins

Question

Im using Maven 3.0.4 and Nexus 2.0.6. I have set up my settings.xml as the Nexus instruction show for using a single repository. I get the error below when maven tries to run maven -U clean.

[ERROR] Plugin org.apache.maven.plugins:maven-clean-plugin:2.4.1 or one of its d
ependencies could not be resolved: Failed to read artifact descriptor for org.ap
ache.maven.plugins:maven-clean-plugin:jar:2.4.1: Could not find artifact org.apa
che.maven.plugins:maven-clean-plugin:pom:2.4.1 in nexus (http://localhost:8081/n
exus/content/groups/public) -> [Help 1]

If I remove the nexus mirror from the settings and go directly to maven central the command works. The settings for the maven repo in nexus show that it is in service and it is in the public group (its listed last).

I am not behind a proxy to access the internet.

Here is my settings.xml

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
<offline>false</offline>
<mirrors>
    <mirror>
        <!--This sends everything else to /public -->
        <id>nexus</id>
        <mirrorOf>*</mirrorOf>
        <url>http://localhost:8081/nexus/content/groups/public</url>
    </mirror>
</mirrors>
<profiles>
    <profile>
        <id>nexus</id>
        <!--Enable snapshots for the built in central repo to direct -->
        <!--all requests to nexus via the mirror -->
        <repositories>
            <repository>
                <id>central</id>
                <url>http://central</url>
                <releases><enabled>true</enabled></releases>
                <snapshots><enabled>true</enabled></snapshots>
            </repository>
        </repositories>
        <pluginRepositories>
            <pluginRepository>
                <id>central</id>
                <url>http://central</url>
                <releases><enabled>true</enabled></releases>
                <snapshots><enabled>true</enabled></snapshots>
            </pluginRepository>
        </pluginRepositories>
    </profile>
    <profile>
        <id>maven-central</id>
        <!--Enable snapshots for the built in central repo to direct -->
        <!--all requests to nexus via the mirror -->
        <repositories>
            <repository>
                <id>central</id>
                <url>http://repo1.maven.org/maven2/</url>
                <releases><enabled>true</enabled></releases>
                <snapshots><enabled>true</enabled></snapshots>
            </repository>
        </repositories>
        <pluginRepositories>
            <pluginRepository>
                <id>central</id>
                <url>http://repo1.maven.org/maven2/</url>
                <releases><enabled>true</enabled></releases>
                <snapshots><enabled>true</enabled></snapshots>
            </pluginRepository>
        </pluginRepositories>
     </profile>
</profiles>
    <activeProfiles>
    <!--make the profile active all the time -->
    <activeProfile>nexus</activeProfile>
</activeProfiles>


</settings>

Can you check if the artifact was downloaded by nexus by accessing it through the web - localhost:8081/nexus/content/groups/public/org/apache/maven/… — Raghuram
Have you checked the access to Nexus via Browser and checked if you can access the artifact via browser as well? — khmarbaise
I've added more detail for my similar situation here: stackoverflow.com/questions/13927806/… — Nicholas Albion
Oddly enough, I'm seeing this behaviour on one machine; and not on a second PC. Both the same settings files, same Nexus set-up. On one the name or id "central" just stops artefacts being found on a build. — will

Sergiu Dumitriu Sergiu Dumitriu · Accepted Answer · 2012-12-21T06:23:54

Make sure the Central proxy repository is properly configured, and the proxied URL is http://repo1.maven.org/maven2/. Check that you can see cached artifacts at the repository's URL, should be http://localhost:8081/nexus/content/repositories/central/org/apache/maven/plugins/maven-clean-plugin/2.4.0/maven-clean-plugin-2.4.1.pom.

Make sure you have a Central proxy at all, is there anything listed at http://localhost:8081/nexus/content/repositories/central/.

If you're behind a proxy, you can configure the proxy under the Default HTTP Proxy Settings (optional) section in the Administration->Nexus pane.

Then, make sure the Public Repositories group repository is configured to include the Central repository in its list of included repositories.

If everything looks fine so far, check the logs, maybe there's a helpful message in there.

Nexus is not caching maven central plugins

3 Answers