Maven is a build automation tool used primarily for Java projects that utilizes a project object model (POM) to manage dependencies and build processes. It was created in 2001 to standardize builds of Apache projects. Some key features include dependency management, a standard project layout, configurable build lifecycles and phases, and plugins for tasks like compiling, testing, packaging, and reporting. Maven aims to provide a uniform build system and is not intended to replace build tools like Ant.

1. Maven overview
Samuel Langlois – May 2017

2. Apache Maven history
• Started by Jason Van Zyl in 2001
o Standardising the build of Apache Turbine
• Version history
o 1.0 in Jul-2004, after loads of betas
o 2.0 in Oct-2005, completely redesigned
o 3.0 in Oct-2010, fully compatible
o 3.5.0 is the latest, released Apr-2017
• Previsouly somewhat controlled by Sonatype
• Strong and stable!

3. Maven is *not* a better Ant
<project>
<target name="compile">
<javac ...>
</target>
<target name="test">
<junit ..>
</target>
<target name="package">
<jar ..>
</target>
</project>
<project>
<groupId>org.alfresco</>
<artifactId>alfresco-core</>
<version>5.1.0</>
<name>Alfresco Core</>
<dependencies>
<dependency>
<groupId>commons-logging</>
<artifactId>commons-logging</>
<version>1.1</>
</dependency>
</dependencies>
</project>
build.xml pom.xml

4. Maven is *not* a better Ant
<project>
<target name="compile">
<javac ...>
</target>
<target name="test">
<junit ..>
</target>
<target name="package">
<jar ..>
</target>
</project>
build.xml pom.xml
CODE
<project>
<groupId>org.alfresco</>
<artifactId>alfresco-core</>
<version>5.1.0</>
<name>Alfresco Core</>
<dependencies>
<dependency>
<groupId>commons-logging</>
<artifactId>commons-logging</>
<version>1.1</>
</dependency>
</dependencies>
</project>
DATA

5. Maven plugins
• Written in Java (MOJO), or ...
• Entry-points are called goals
• Examples:
o Core
 maven-compiler-plugin
 maven-resources-plugin - including filtering
 maven-surefire-plugin - executes tests
o Reporting
 maven-javadoc-plugin
 maven-findbugs-plugin
o Code Generation
 antlr3-maven-plugin
o maven-alfresco-plugin !!
o .......

6. Configuring a plug-in
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
<debug>false</debug>
</configuration>
</plugin>

7. Maven phases
Phase Default binding for jar packaging
initialize
generate-sources
process-resources resources:resources
compile compiler:compile
generate-test-sources
process-test-resources resources:testResources
test-compile compiler:testCompile
test surefire:test
package jar:jar
pre-integration-test
integration-test
post-integration-test
install install:install
deploy deploy:deploy

8. Plugging a plug-in
<plugin>
<artifactId>maven-jetty-plugin</artifactId>
<executions>
<execution>
<id>start-jetty</id>
<phase>pre-integration-test</phase>
<goals> <goal>run</goal> </goals>
</execution>
<execution>
<id>stop-jetty</id>
<phase>post-integration-test</phase>
<goals> <goal>stop</goal> </goals>
</execution>
</executions>
<configuration>
<port>9876</port>
</configuration>
</plugin>

9. Maven conventions
• tree layout
o pom.xml
o src
 main
• java
• resources
 test
• java
• resources
o target
• tests are executed as part of the build
Follow the Maven way!

10. Maven dependency
A dependency (internal or external) is made of:
• mandatory : GAV
o groupId (org.alfresco)
o artifactId (alfresco-datamodel)
o version
 release: 4.1.0
 snapshot: 4.1.0-SNAPSHOT
• optionally:
o scope (compile, test, provided, ...)
o classifier (jdk6, sources, javadocs, ...)
Dependencies are transitive!
• mvn dependency:tree dependency:list

11. Maven dependency management
mvnlocal Maven repo
~/.m2/repository
Maven Central
http://repo.maven.apache.org/maven2/
mvn install

12. Maven dependency management
mvnmvn install
Team Repo
Maven Central
http://repo.maven.apache.org/maven2/
local Maven repo
~/.m2/repository

13. Invoking Maven
• call a phase
o mvn clean install
o mvn test
• call a goal
o mvn surefire:test
o mvn javadoc:javadoc
• Useful switches
o -o : offline
o -U : force check for snapshot updates
o -X : verbose, to check plugin configuration
• Adding command-line params for plugins
o -DskipTests
o -Dtest=MyClassTest

14. Multimodule builds
• call sub-projects in parent folder
<packaging>pom</packaging>
<modules>
<module>core</module>
<module>web-client</module>
</modules>
• pom inheritance in sub-projects
<parent>
<groupId>...
<artifactId>...
<version>...
</parent>
• Computing the actual pom
mvn help:effective-pom

15. Maven profiles
• conditional parts in the pom.xml
o plug/unplug a submodule
o run a different set of tests
o test various platforms
o ...
• Triggering a profile
o command line: -Pprofile1,!profile3
o presence/absence of a property
o automatic: JDK, OS, platform, existence of a file, …

16. IDE integration
• "Old school": Maven generating IDE project
o mvn eclipse:eclipse [-DdownloadSources=true]
o mvn idea:idea
o mvn netbeans:netbeans
• Recommended: IDE directly reading pom.xml
o m2e plugin, included in "Eclipse IDE for Java Devs"

17. Reporting - Maven site

18. Reporting - Sonar

19. Want some more?
• Maven books from Sonatype
https://www.sonatype.com/ebooks
• pom.xml reference
• Maven Plugins reference
o Apache
o Codehaus