Maven

created by Noah

  • Project and Build Management Tool

  • Standardization (convention over configuration)

  • Dependency management

  • Documentation & reporting

  • Process-Management

Project Object Model

  • pom.xml
  • Central config file
<!-- Minimal POM -->
<project>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.unique.identifier.of.project</groupId>
    <artifactId>artifact-name</artifactId>
    <version>1</version>
</project>

Properties

Specified by <properties><PROP> (VALUE) and referenced by ${PROP}. Maven may also declare default properties (${project.PROP}, ${maven.PROP}). May also be specified on the command line

Dependencies

Specifies dependencies of artifacts. Dependencies are automatically resolved and pulled from a repository. Declared by <dependencies><dependency> (groupId, artifactId, version, scope, ...)

Inheritance

POMs inherit elements from parent POMs. The root of the inheritance hierarchy is the "Super POM". Specified by either <parent> (groupId, artifactId, version) or <modules><module> (RELATIVE_PATH_TO_CHILD_POM)

Used to specify common elements in a root/parent POM

Build Environment

Specifies the build environment Declared in <build>

  • directory
  • Output directory
  • finalName
  • Final artifact name
  • sourceDirectory
  • outputDirectory
  • Contains class files for sources
  • testSourceDirectory
  • testOutputDirectory
  • Contains class files for test sources
  • resources > resource > ...
  • testResources > testResource > ...
  • plugins > plugin > groupId, artifactId, version, ...

Plugins

Used to customize the build lifecycle. Default plugins are part of the "Super POM"

Profiles

Profiles can be used to modify elements of the POM depending on activation conditions Specified by <profiles><profile> (id, activation, MODIFICATIONS, ...). May also be activated by the command line

For examlple used for specifing file paths for windows and linux

Repositories

Tells maven from where to fetch dependencies and other artifacts. Specified by <repositories><repository> (id, name, url, ...)

Additionally to these remote repositories there is always the local repository ~/.m2 that is mostly used as an artifact cache

Plugin Repositories

Tells maven from where to fetch plugin artifacts. Specified by <pluginRepositories><pluginRepository>

Build Lifecycle

Cleaning

  • clean
  • Remove all files from previous bilds

Building (default)

  • validate
  • Validate necessary information is available & correrct
  • initialize
  • Initialize build
  • compile
  • Compile sources
  • test-compile
  • Compile test sources
  • test
  • Run tests
  • package
  • Generate artifact
  • integration-test
  • Deploy the artifact & run integration tests
  • verify
  • Verify the artifact (e.g. quality criteria)
  • install
  • Install to local repository
  • deploy
  • Deploy to remote repository

Site documentation

  • site
  • Generate documentation
  • site-deploy
  • Deploy documentation

Plugin Goals

Plugins have different goals (PLUGIN:GOAL), these make up the basic building blocks of the process. They are bound to different build phases, and are therefore run during the build lifecycle

Default Project Structure

pom.xml

src/
    main/
        java/
        resouces/

    test/
        java/
        resources/

    it/ (integration tests)

    site/ (documentation)

LICENSE.txt
README.txt
NOTICE.txt

Maven Assemblies

The maven-assembly-plugin can be used to distribute the project (.jars, README, LICENSE, documentation, ...) For each type of distribution a descriptor is created, that specifies the format and content of the distribution archive

Apache Ant

No default build lifecycle. Low standardization