Appendix H. About Apache Maven

Apache Maven is a distributed build automation tool used in Java application development to create, manage, and build software projects. Maven uses standard configuration files called Project Object Model, or POM, files to define projects and manage the build process. POMs describe the module and component dependencies, build order, and targets for the resulting project packaging and output using an XML file. This ensures that the project is built in a correct and uniform manner.

Maven achieves this by using a repository. A Maven repository stores Java libraries, plug-ins, and other build artifacts. The default public repository is the Maven 2 Central Repository, but repositories can be private and internal within a company with a goal to share common artifacts among development teams. Repositories are also available from third-parties. AMQ includes a Maven repository that contains tested and supported versions of the AMQ 7 Java packages and dependencies.

For more information about Maven, see Welcome to Apache Maven.

For more information about Maven repositories, see Apache Maven Project - Introduction to Repositories.

H.1. About the Maven POM File

The Project Object Model, or POM, file is a configuration file used by Maven to build projects. It is an XML file that contains information about the project and how to build it, including the location of the source, test, and target directories, the project dependencies, plug-in repositories, and goals it can execute. It can also include additional details about the project including the version, description, developers, mailing list, license, and more. Maven favors "convention over configuration". A pom.xml file requires minimal configuration and will default all other values.

The schema for the pom.xml file can be found at http://maven.apache.org/maven-v4_0_0.xsd.

For more information about POM files, see the Apache Maven Project POM Reference.

Minimum Requirements of a Maven POM File

The minimum requirements of a pom.xml file are as follows:

  • project root
  • modelVersion
  • groupId - the id of the project’s group
  • artifactId - the id of the artifact (project)
  • version - the version of the artifact under the specified group

Example: Sample pom.xml File

A basic pom.xml file might look like this:

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.jboss.app</groupId>
  <artifactId>my-app</artifactId>
  <version>1</version>
</project>

H.2. About the Maven Settings File

The Maven settings.xml file contains user-specific configuration information for Maven. It contains information that must not be distributed with the pom.xml file, such as developer identity, proxy information, local repository location, and other settings specific to a user.

There are two locations where the settings.xml can be found:

  • In the Maven installation: The settings file can be found in the $M2_HOME/conf/ directory. These settings are referred to as global settings. The default Maven settings file is a template that can be copied and used as a starting point for the user settings file.
  • In the user’s installation: The settings file can be found in the ${user.home}/.m2/ directory. If both the Maven and user settings.xml files exist, the contents are merged. Where there are overlaps, the user’s settings.xml file takes precedence.

Example: Maven Settings File

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
  <profiles>
    <!-- Configure the JBoss AMQ Maven repository -->
    <profile>
      <id>jboss-amq-maven-repository</id>
      <repositories>
        <repository>
          <id>jboss-amq</id>
          <url>file:///path/to/repo/</url>
          <releases>
            <enabled>true</enabled>
          </releases>
          <snapshots>
            <enabled>false</enabled>
          </snapshots>
        </repository>
      </repositories>
      <pluginRepositories>
        <pluginRepository>
          <id>jboss-amq-maven-plugin-repository</id>
          <url>file://path/to/repo</url>
          <releases>
            <enabled>true</enabled>
          </releases>
          <snapshots>
            <enabled>false</enabled>
          </snapshots>
        </pluginRepository>
      </pluginRepositories>
    </profile>
  </profiles>
  <activeProfiles>
    <!-- Optionally, make the repository active by default -->
    <activeProfile>jboss-amq-maven-repository</activeProfile>
  </activeProfiles>
</settings>

The schema for the settings.xml file can be found at http://maven.apache.org/xsd/settings-1.0.0.xsd.

Revised on 2017-12-14 16:57:53 EST