Maven

Maven is a build tool for Java projects.

Concepts

  • Projects are the units of work Maven manages.
    • The POM (pom.xml) file is the core of a Maven project's configuration.
    • Project inheritance allows POMs to inherit from other POMs.
      • By default, all POMs inherit the Super POM, unless the /project/parent element is specified.
    • Project aggregation is similar to inheritance, but specifies a child module (/project/modules/module) in the parent POM instead
  • A BOM is a type of POM specifying dependencies which may itself be included for these transitive dependencies, centralising their management across numerous projects.
  • Goals are similar to tasks in other build systems, and may accept parameters using the -D CLI argument. Goals are namespaced by the ID of the plugin which provides them.
  • Plugins provide goals or report types.
  • Profiles as per-project, per-user, or global configurations which can be used to override portions of a POM.
  • Phases define the categories of goals with a project's build lifecycle. Different packaging types will map different goals to different phases.
  • Archetypes provide predefined templates which accept some user input to generate a skeleton project.
  • A repository contains built artifacts and dependencies.
    • Each user's local repository caches artifacts and dependencies to speed up subsequent installation.
    • A remote repository may be accessed over a network.
  • Maven uses two fields to identify projects:
    • groupId is typically set to the organisation name.
    • artifactId is used to identify the project, relative to the groupId.

CLI

mvn:

  • -B or --batch-mode is non-interactive.
  • -D<property>=<value> or --define <property>=<value> set a system property value.
  • -P profile1,profile2 specifies a comma-delimited set of profiles to activate.
  • -o or --offline forces use of dependencies cached in the local repository.