This document provides a comprehensive introduction to Apache Maven, detailing its features as a build, dependency management, and project management tool. Key concepts include the Project Object Model (POM), lifecycle phases, dependency management, and the use of repositories for storing build artifacts. It also addresses plugin usage, project configuration, and tips for effective integration with IDEs like Eclipse.

1. Basic introduction in Maven
•
Introduction
•
POM (Project Object Model)
•
Lifecycle
•
Repository
•
Dependency Management
•
Reporting
•
IDE Integration
•
Tips & Tricks
Heiko Scherrer

2. What is Maven?
•
A build tool like Apache Ant but:
●
Configure your build, don't script it
●
Define what you build, not how!
•
A dependency management tool
●
Coherent organization of dependencies
•
A project management tool
Take back control!
Heiko Scherrer

3. What is Maven?
•
Currently using Maven2.
Maven3 is almost backward compatible
•
Benefit of a wide range of plugins to
setup your build and reporting
•
Maven repository server, e.g. Sonatype's
Nexus
Heiko Scherrer

4. Maven vs. Ant – Why not Ant?
•
“Convention over Configuration”
•
Appreciate for building complex
modularized applications
•
Based on a repository to store and
resolve artifacts
•
Maven doesn't have to know about
directory structures (use defaults)
Heiko Scherrer

5. Downside of Maven
•
“Convention over Configuration”
•
Exceptions are less meaningful and
configuration errors hard to find
•
Plugins are less documented
Heiko Scherrer

6. Basic introduction in Maven
•
Introduction
•
POM (Project Object Model)
•
Lifecycle
•
Repository
•
Dependency Management
•
Reporting
•
IDE Integration
•
Tips & Tricks
Heiko Scherrer

7. What represents a project ?
•
Each project has a project descriptor
(pom.xml)
•
A project is determined using Maven
coordinates
groupId:artifactId:version:classifier:type
•
Project Object Model (POM) files support
inheritance
Heiko Scherrer

8. Standard directory layout
•
Take advantage of
Mavens default
configuration - setup a
standard directory layout
•
Maven Archtype plugin
creates project structure
•
The target directory is
generated after the first
build run
Heiko Scherrer

9. POM – Project Object Model (I)
•
Define your project <project ...>
coordinates <modelVersion>4.0.0</modelVersion>
<groupId>org.openwms</groupId>
•
Set a packaging type <artifactId>org.openwms.core</artifactId>
<version>1.0.1-SNAPSHOT</version>
-> what to build <packaging>jar</packaging>
List dependencies,
<dependencies>
•
<dependency>
you need for your <groupId>junit</groupId>
<artifactId>junit</artifactId>
project in different <version>${junit.version}</version>
<scope>test</scope>
scopes
</dependency>
</dependencies>
•
Use custom </project>
properties
Heiko Scherrer

10. POM - Scopes
•
COMPILE
Included in compilation, packaged and delivered
•
PROVIDED
Included in compilation, but not packaged. Expected to be
provided at runtime
•
RUNTIME
Not included in compilation classpath, but expected at runtime
(Class.forName...)
•
TEST
Only included in test classpath and test phase; not delivered
•
SYSTEM
Like provided, but must be referenced directly. Used for non
Maven artifacts
Heiko Scherrer

11. POM Inheritance
•
A super POM comes with your local Maven
installation (maven2.jar#pom-4.0.0.xml)
•
POM files inherit configuration from a parent
project
•
Common used dependencies or configuration
snippets shall be moved to a parent project
•
That way it is possible to build complex
inheritance strategies
•
Find the effective POM:
mvn help:effective-pom
Heiko Scherrer

12. Grouping & Inheritance
•
Building modules to group projects
• Use the packaging type pom and define
submodules
•
Group modules and configure build with
Profiles
•
Use inheritance to follow DRY principle
Heiko Scherrer

13. POM – Project Object Model (II)
<project ...>
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.openwms</groupId>
<artifactId>org.openwms</artifactId>
•
Define a parent <version>1.0.1-SNAPSHOT</version>
</parent>
project <artifactId>org.openwms.core</artifactId>
<packaging>pom</packaging>
•
Project coordinates <name>OpenWMS CORE module</name>
<modules>
<module>org.openwms.core.domain</module>
Project name and a
</modules>
•
<build>
list of submodules <plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-
•
Override plugin <configuration>
plugin</artifactId>
<source>1.6</source>
configuration <target>1.6</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
Heiko Scherrer

14. Basic introduction in Maven
•
Introduction
•
POM (Project Object Model)
•
Lifecycle
•
Repository
•
Dependency Management
•
Reporting
•
IDE Integration
•
Tips & Tricks
Heiko Scherrer

15. Lifecycle, Phases, Plugins and Goals
•
Maven uses plugins to accomplish it's work
•
Each plugin offers one or more goals
•
A goal is specific to a plugin -
comparable to an Ant target
•
Most plugins are developed and driven by the
community
•
Plugin goals are documented on the generated Maven
site
Plugin Goal
• Calling a single plugin goal: mvn compiler:compile
Heiko Scherrer

16. Lifecycles, Phases, Plugins and Goals
•
The Lifecycle is a pre-defined procedural process for
building and distributing a particular artifact
•
A Phase is one step in Mavens Build Lifecycle
●
Plugin goals are attached to an execution Phase
●
Each Phase can perform one or more plugin goals
•
Kick a Lifecycle Phase execution:
mvn clean or mvn site
• 3 standard Lifecycles : clean, default, site
•
Plugins can define own Lifecycles (see Flex plugin)
Heiko Scherrer

17. Standard Lifecycle - Clean
•
Provided by the
clean plugin
•
Pre-configured in the pre-clean
Super POM
• Run mvn clean to
execute all three clean
phases within the
Lifecycle
•
Deletes build post-clean
directory
${basedir}/target
Heiko Scherrer

18. Standard Lifecycle - Default
validate
•
21 phases
•
Validate project
compile
completeness for build run
•
Compile source code
test
•
Run unit tests
•
Package in distributable
format package
•
Install to local repository
install
•
Deploy; copies the artifacts
to a remote repository deploy
Heiko Scherrer

19. Basic introduction in Maven
•
Introduction
•
POM (Project Object Model)
•
Lifecycle
•
Repository
•
Dependency Management
•
Reporting
•
IDE Integration
•
Tips & Tricks
Heiko Scherrer

20. Local Maven Repository
• When executing the Lifecycle phase install,
Maven populates a local repository with
artifacts
• Local repository: ~/.m2/repository
•
Dependencies and custom deliverables are
stored hierarchically
• The groupId is interpreted as directory path
• The artifactId and version define the name
of the artifact
Heiko Scherrer

21. Remote Maven Repository
•
A Remote repository is a central, company-
wide storage for build artifacts
•
Serves as
●
a Proxy (to minimize bandwidth)
●
a storage for own project artifacts
(accessible by Maven or web UI)
•
Sonatype Nexus Repository Manager is
OpenSource (comm. version available)
• Copy to central repo: mvn deploy
Heiko Scherrer

22. Remote Maven Repository II
Heiko Scherrer

23. Remote Maven Repository III
Deploy remote <distributionManagement>
•
In your top-level pom <repository>
<id>org_openwms_rudi_releases</id>
<name>OpenWMS Internal Releases</name>
<url>http://rudi:8081/nexus/content/rel</url>
</repository>
•
Define repository <snapshotRepository>
server for snapshots
<id>org_openwms_rudi_snapshots</id>
<name>OpenWMS Internal Snapshots</name>
<url>http://rudi:8081/nexus/content/snap</url>
and releases </snapshotRepository>
<site>
<id>org_openwms_sf</id>
<name>OpenWMS Website</name>
Server definition for
<url>scp://${distribution.web.server}</url>
• </site>
website deployment </distributionManagement>
•
Use placeholders!
Heiko Scherrer

24. Remote Maven Repository IV
<settings>
~/.m2/settings.xml: <servers>
<server>
<id>org_openwms_rudi_releases</id>
•
Server credentials <username>USERNAME</username>
<password>PASSWORD</password>
used to deploy
</server>
</servers>
<mirrors>
Route all requests to a
<mirror>
• <id>all</id>
<mirrorOf>*</mirrorOf>
proxy <url>http://rudi:8081/nexus/content/all</url>
</mirror>
</mirrors>
•
Manage exception <repositories>
<repository>
routes
<id>org_openwms_sf_snap</id>
<url>http://rudi:8081/nexus/content/snap</url>
<releases><enabled>false</enabled></releases>
<snapshots><enabled>true</enabled></snapshots>
→ Demo </repository>
</repositories>
</settings>
Heiko Scherrer

25. Basic introduction in Maven
•
Introduction
•
POM (Project Object Model)
•
Lifecycle
•
Repository
•
Dependency Management
•
Reporting
•
IDE Integration
•
Tips & Tricks
Heiko Scherrer

26. Dependency Management
•
Manage common dependency
declarations in parent pom:
<dependencyManagement>
•
Manage common plugin configuration in
parent pom: <pluginManagement>
•
Define repository locations for artifact &
plugin repositories in parent pom
•
Use variables for substitute versions
Heiko Scherrer

27. Dependency Management - Example
<dependencies>
<dependency>
•
Add dependencies <groupId>javaee</groupId>
<artifactId>javaee-api</artifactId>
<scope>provided</scope>
provided by the EJB </dependency>
container
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.12</version>
<exclusions>
•
Exclude <exclusion>
<groupId>com.sun.jmx</groupId>
<artifactId>jmxri</artifactId>
dependencies when </exclusion>
</exclusions>
</dependency>
necessary <dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
•
Set the proper <scope>test</scope>
</dependency>
scope to avoid <dependency>
<groupId>commons-lang</groupId>
packaging of
<artifactId>commons-lang</artifactId>
<version>2.4</version>
<scope>compile</scope>
dependencies
</dependency>
</dependencies>
Heiko Scherrer

28. Worth to mention
•
Resource filtering
•
Profiles
•
Classifiers
Heiko Scherrer

29. Basic introduction in Maven
•
Introduction
•
POM (Project Object Model)
•
Lifecycle
•
Repository
•
Dependency Management
•
Reporting
•
IDE Integration
•
Tips & Tricks
Heiko Scherrer

30. Reporting & Site Generation
ASDoc Cobertura
Website
Javadoc
JXR
PMD Checkstyle
Taglist
JDepend CPD
Heiko Scherrer

31. Reporting & Site Generation
• Run site generation: mvn site
•
Maven-site-plugin
• Site content: ${basedir}/src/site
•
Accepted formats: apt, fml, xdoc,
DocBook, …
Heiko Scherrer

32. Reporting & Site Generation
•
Report generation is part of site
•
Site customization is done within
<reporting> section
•
Useful plugins:
maven-project-info-reports-plugin,
dashboard-maven-plugin,
cobertura-maven-plugin,
maven-surefire-report-plugin,
maven-javadoc-plugin
•
→ Demo
Heiko Scherrer

33. Basic introduction in Maven
•
Introduction
•
POM (Project Object Model)
•
Lifecycle
•
Repository
•
Dependency Management
•
Reporting
•
IDE Integration
•
Tips & Tricks
Heiko Scherrer

34. IDE Integration (Eclipse)
•
Usually each IDE has its own project setting files
•
Avoid sharing platform specific files within your
VCS
• Import pom.xml as Maven project → Eclipse demo
• Use maven-eclipse-plugin to add particular
project facets: mvn eclipse:eclipse
•
Use the IDE to develop – not to build.
→ Keep Maven out of development process
Heiko Scherrer

35. IDE Integration II (Eclipse)
•
Install m2eclipse:
http://m2eclipse.sonatype.org/sites/m2e
•
m2eclipse comes with Maven3 beta, change
manually to local Maven2 installation
•
In addition to the local and remote repository,
m2eclipse uses the workspace as 1st. Repository
•
Use favorite Run Configurations to run Maven
Heiko Scherrer

36. Basic introduction in Maven
•
Introduction
•
POM (Project Object Model)
•
Lifecycle
•
Repository
•
Dependency Management
•
Reporting
•
IDE Integration
•
Tips & Tricks
Heiko Scherrer

37. Tips & Tricks
• Download sources mvn dependency:sources
• Define <server> in your settings.xml to store your
credentials
• Add -DskipTests to bypass test phase
• Add -U to update snapshot dependencies manually
•
m2e: Nested projects lead to artifact resolving
errors
Heiko Scherrer

38. Tips & Tricks II
•
Aggregate common config in top-level pom
•
SVN ignore IDE specific files and use pom as
project descriptor at all
•
Don't commit binaries or generated files to VCS
Heiko Scherrer

39. Q&A
Heiko Scherrer

40. Document History
•
Initial svn rev. [1472];
•
Updated svn rev. [1475];2011-01-16
Heiko Scherrer