Maven.

~/.m2/settings.xml.

Maven package repositories

Maven Central official aliases (in past - mirrors):

Spring repos is server by Artifactory and available on:

Sonatype Releases Repository:

https://oss.sonatype.org/content/repositories/releases/

NetBeans:

http://bits.netbeans.org/maven2/

JBoss Enterprise Maven Repository:

https://maven.repository.redhat.com/ga/

https://mvnrepository.com/repos: List of popular public Maven repositories.
http://blog.sonatype.com/2010/10/new-official-maven-central-repository-in-europe/: New official Maven Central repository in Europe.

Generate simple project

mvn archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

mvn archetype:generate -DinteractiveMode=false \
  -DgroupId=com.mycompany.app -DartifactId=my-app \
  -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeGroupId=org.apache.maven.archetypes

Debug Maven build.

Run build with -X option for verbose logging.

Project directory layout.

http://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html: Introduction to the Standard Directory Layout.

Search for maven artifact by Java package or class name.

Get help on Maven plug-in

$ mvn help:describe -DartifactId=maven-war-plugin -DgroupId=org.apache.maven.plugins
$ mvn help:describe -Dcmd=dependency:resolve -Ddetail

$ mvn -X ...

What actual code processed by Maven (dump Maven config):

$ mvn help:effective-settings
$ mvn help:effective-pom

Investigating and resolving dependencies

List dependencies:

$ mvn dependency:tree
$ mvn dependency:list

Resolve dependencies:

$ mvn dependency:resolve
$ mvn dependency:resolve-plugins

Just download dependencies:

$ mvn dependency:get

or download a specific dependency (to the local M2 cache):

$ mvn dependency:get -Dartifact=$groupId:$artifactId:$version
$ mvn dependency:get -DgroupId=$groupId -DartifactId=artifactId -Dversion=$version
$ mvn dependency:get -DgroupId=$groupId -DartifactId=artifactId -Dversion=$version -DremoteRepositories=$repoUrl

Reason for inclusion or omitting dependencies:

$ mvn dependency:tree -Dverbose=true

Update pom.xml with latest dependency version:

$ mvn versions:use-latest-releases -Dincludes=$groupId:$artifactId

Print build classpath:

$ mvn dependency:build-classpath

Copy specific dependency to local directory:

mvn dependency:copy -Dartifact=...
mvn dependency:copy -Dartifact=... -DoutputDirectory=.

Download POM, sources or javadoc:

mvn dependency:copy -Dartifact=$grp:$art:$ver:pom
mvn dependency:copy -Dartifact=$grp:$art:$ver:jar
mvn dependency:copy -Dartifact=$grp:$art:$ver:jar:sources
mvn dependency:copy -Dartifact=$grp:$art:$ver:jar:javadoc

Copy all dependencies to local folder (default is target/dependencies):

mvn dependency:copy-dependencies
mvn dependency:copy-dependencies -Dclassifier=sources
mvn dependency:copy-dependencies -DoutputDirectory=libs

Download all external dependencies sources and javadocs

mvn dependency:resolve -Dclassifier=javadoc
mvn dependency:resolve -Dclassifier=sources

Build sources and javadoc

mvn source:jar
mvn javadoc:jar

To install sources or javadoc locally:

mvn source:jar install
mvn javadoc:jar install
mvn source:jar javadoc:jar install

To do that automatically on jar lifecycle:

<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-source-plugin</artifactId>
      <executions>
        <execution>
          <id>attach-sources</id>
          <goals>
            <goal>jar</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

Force update of dependencies

You can try redownload snapshots by:

$ mvn -U compile

You can fix damaged local ~/.m2 with:

$ mvn dependency:purge-local-repository

In order to perform really clean download:

$ mvn -Dmaven.repo.local=$HOME/.my/other/repository clean install

Find newer library and plugin versions

Check commands from versions-maven-plugin:

$ mvn versions:display-dependency-updates
$ mvn versions:display-plugin-updates

Update pom.xml with latest dependency version:

$ mvn versions:use-latest-releases -Dincludes=$groupId:$artifactId

Update all versions in pom.xml to latest:

$ mvn versions:use-latest-releases
$ rm pom.xml.versionsBackup

or:

$ mvn versions:use-latest-releases -DgenerateBackupPoms=false

Remove all SNAPSHOT versions:

$ mvn versions:use-releases -DgenerateBackupPoms=false

More details about versions plugin:

$ mvn help:describe -Dplugin=versions
$ mvn help:describe -Dplugin=versions -Ddetail

Run Java main from Maven.

mvn exec:java -Dexec.mainClass="com.vineetmanohar.module.Main" -Dexec.args="arg0 arg1 arg2"

How to run single unit test?

test property substituded to **/${test}.java pattern and override any include/exclude patterns:

$ mvn test -Dtest=SeriousComponentTest

or mostly same:

$ mvn test-compile surefire:test -Dtest=RunMe

How do I skip the tests during the default lifecycle?

$ mvn -DskipTests package
$ mvn -Dmaven.test.skip=true package

Deploy parent pom without building children.

$ mvn -N deploy

Install file to local repository

$ mvn install:install-file -Dfile=... -DgroupId=... -DartifactId=... -Dversion=...

Additional option provides packaging type (JAR/WAR), source and javadoc files:

-Dpackaging=...
-Dsource=...
-Djavadoc=...

Maven tutorial.

Maven FAQ.

Maven plugins.

Maven config location.