12.9. Lifecycles and Phases

Maven build lifecycles

Maven is build around the concepts of build Lifecycles, Phases, Plugins and Goals.

A lifecycle is an abstract concept around the expected stages in a project’s development. It is a sequence of named stages i.e phases.

Maven has three defined Lifecycles.

• clean: cleans the project environment.
• default (build): builds and deploys the project.
• site: creates a website for the project.

Phases are the steps in a lifecycle which are executed sequentially.

• Executing a phase means executing all the previous phases.
• Each phase may or may not perform some operations.
• Maven defines 28 phases.
  • the default lifecycle has 21 phases,
  • the clean lifecycle has 3 phases, and
  • the site lifecycle has 4 phases.

A plugin is a collection of goals, which are specific tasks contributing to building and managing projects. One can think of plugins as classes and goals as methods.

Figure from this medium.com article.

The clean lifecycle

<phases>
  <phase>pre-clean</phase>
  <phase>clean</phase>
  <phase>post-clean</phase>
</phases>
<default-phases>
  <clean>
    org.apache.maven.plugins:maven-clean-plugin:2.5:clean
  </clean>
</default-phases>

http://maven.apache.org/ref/3.6.3/maven-core/lifecycles.html#clean_Lifecycle

The default lifecycle

• validate: check if all information necessary for the build is available.
• compile: compile the source code.
• test-compile: compile the test source code.
• test: run unit tests.
• package: package compiled source code into the distributable format (e.g. .jar).
• integration-test: process and deploy the package if needed to run integration tests.
• install: install the package to a local repository.
• deploy: copy the package to the remote repository.

Figure from this article.

Plugin bindings for jar packaging:

<phases>
  <process-resources>
    org.apache.maven.plugins:maven-resources-plugin:2.6:resources
  </process-resources>
  <compile>
    org.apache.maven.plugins:maven-compiler-plugin:3.1:compile
  </compile>
  <process-test-resources>
    org.apache.maven.plugins:maven-resources-plugin:2.6:testResources
  </process-test-resources>
  <test-compile>
    org.apache.maven.plugins:maven-compiler-plugin:3.1:testCompile
  </test-compile>
  <test>
    org.apache.maven.plugins:maven-surefire-plugin:2.12.4:test
  </test>
  <package>
    org.apache.maven.plugins:maven-jar-plugin:2.4:jar
  </package>
  <install>
    org.apache.maven.plugins:maven-install-plugin:2.4:install
  </install>
  <deploy>
    org.apache.maven.plugins:maven-deploy-plugin:2.7:deploy
  </deploy>
</phases>

Read more here.

The site lifecycle

<phases>
  <phase>pre-site</phase>
  <phase>site</phase>
  <phase>post-site</phase>
  <phase>site-deploy</phase>
</phases>
<default-phases>
  <site>
    org.apache.maven.plugins:maven-site-plugin:3.3:site
  </site>
  <site-deploy>
    org.apache.maven.plugins:maven-site-plugin:3.3:deploy
  </site-deploy>
</default-phases>

Read more here.