Is there a way to make Maven download snapshot versions automatically?

Question

So I have a project that depends on a snapshot version of another project. The dependency is:

<dependency>
  <groupId>org.oop</groupId>
  <artifactId>oop</artifactId>
  <version>0.9.9-SNAPSHOT</version>
</dependency>

For the oop project, I did do a 'mvn clean deploy', so the snapshot version should be somewhere in the maven central repository. But when I do a mvn clean install, the snapshot dependency above cannot be resolved and I get this:

Missing:

1) org.oop:oop:jar:0.9.9-SNAPSHOT

Try downloading the file manually from the project website.

Then, install it using the command: mvn install:install-file -DgroupId=org.oop -DartifactId=oop -Dversion=0.9.9-SNAPSHOT -Dpackaging=jar -Dfile=/path/to/file

Alternatively, if you host your own repository you can deploy the file there: mvn deploy:deploy-file -DgroupId=org.oop -DartifactId=oop -Dversion=0.9.9-SNAPSHOT -Dpackaging=jar -Dfile=/path/to/file -Durl=[url] -DrepositoryId=[id]

Is there a way to make maven download the snapshot automatically? I must be missing something here.

EDIT1: On my settings.xml I have:

   <server>
      <id>sonatype-nexus-snapshots</id>
      <username>XXXXXX</username>
      <password>XXXXXX</password>
    </server>

    <server>
      <id>sonatype-nexus-staging</id>
      <username>XXXXXX</username>
      <password>XXXXXX</password>
    </server>

EDIT2:

Answer 1

Just add this to your ~/.m2/settings.xml:

<profiles>
  <profile>
     <id>allow-snapshots</id>
        <activation><activeByDefault>true</activeByDefault></activation>
     <repositories>
       <repository>
         <id>snapshots-repo</id>
         <url>https://oss.sonatype.org/content/repositories/snapshots</url>
         <releases><enabled>false</enabled></releases>
         <snapshots><enabled>true</enabled></snapshots>
       </repository>
     </repositories>
   </profile>
</profiles>

Answer 2

To update snapshots, try with the -U option

-U,--update-snapshots                  Forces a check for updated
                                       releases and snapshots on remote
                                       repositories

However, you said:

I did do a 'mvn clean deploy', so the snapshot version should be somewhere in the maven central repository.

This is just not possible, your snapshot is going somewhere else. If I do a mvn clean deploy without configuring my personal repository I get:

Deployment failed: repository element was not specified in the POM inside distributionManagement element or in -DaltDeploymentRepository=id::layout::url parameter

To enable deployment, there is some configuration to be added to pom.xml, like for instance:

<distributionManagement>

    <!-- Publish versioned releases here -->
    <repository>
        <id>myrepo</id>
        <name>My releases</name>
        <url>http://nexus.mycompany.com/nexus/content/repositories/releases</url>
    </repository>

    <!-- Publish snapshots here -->
    <snapshotRepository>
        <id>myrepo</id>
        <name>my snapshots</name>
        <url>http://nexus.mycompany.com/nexus/content/repositories/snapshots</url>
    </snapshotRepository>

</distributionManagement>

<repositories>
    <repository>
        <id>myrepo</id>
        <name>My Public Repository</name>
        <url>http://nexus.mycompany.com/nexus/content/groups/public</url>
        <releases>
            <enabled>true</enabled>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
</repositories>