Maven Introduction

MAVEN GUIDE

mvn archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4 -DinteractiveMode=false

What does it do?

• Execute the Maven goal archetype:generate, and passed in various parameters to that goal.
• archetype is the plugin that provides the goal. (goal is something like an ant task).
• archetype:generate goal creates a simple project based on maven-archetype-quickstart archetype.

What is a plugin

• Collection of goals with a general common purpose
• For example jboss-maven-plugin deals with various jboss items

mvn package

• This is a phase rather than a goal.
• Phase is a step in build cycle which is ordered sequence of phases.
• When a phase is given, Maven will execute every phase in the sequence up to and including the one defined.
• For example, if we execute the compile phase, the phases that actually get executed are:
  validate
  generate-sources
  process-sources
  generate-resources
  process-resources
  compile

Test your compiled and packaged jar

• java -cp target/my-app-1.0-SNAPSHOT.jar com.mycompany.app.App

Java 9 or later

• By default your version of Maven might use an old version of the maven-compiler-plugin that is not compatible with Java 9 or later versions.
• To target Java 9 or later, you should at least use version 3.6.0 of the maven-compiler-plugin and set the maven.compiler.release property to the Java release you are targetting
  (e.g. 9, 10, 11, 12, etc.)

Maven Phases

• validate – check if all the information is available
• compile – compile the source code of the product
• test – test complied code using suitable unit testing product
• package – packagae the compiled code and package it in distributable format – jar
• integration-test – process and deploy the package into an environment where integration tests can be run
• verify – run checks to verify if the package is valid and meets quality criteria
• install – install the package in local repository for use in dependency in other projects locally
• deploy – done in an integration environment, copies the final package to remote repository for sharing with other developers and projects

Two special Maven phases

• clean – cleans up artifacts created by prior builds
• site – generates site documentation for this project

Phase Goal Relationship

• Phases are mapped to goals
• Specific goals executed per phase are dependent on packaging type of product.
• Project type jar – package executes jar.jar
• Project type war – package executes war.war

Phase & Goal execution order

• Phases and goals can be executed in sequence
• mvn clean dependency:copy-dependencies package

Maven Default Folders

• src/main/java Application/Library sources
• src/main/resources Application/Library resources
• src/main/filters Resource filter files
• src/main/webapp Web application sources
• src/test/java Test sources
• src/test/resources Test resources
• src/test/filters Test resource filter files
• src/it Integration Tests (primarily for plugins)
• src/assembly Assembly descriptors
• src/site Site
• LICENSE.txt Project’s license
• NOTICE.txt Notices and attributions required by libraries that the project depends on
• README.txt Project’s readme