Apache Maven

Péter Jeszenszky Faculty of Informatics, University of Debrecen

jeszenszky.peter@inf.unideb.hu

Last modified: February 23, 2021

mailto:jeszenszky.peter@inf.unideb.hu

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Apache Maven ● A software project management and comprehension

tool with the following objectives: – Making the build process easy. – Providing a uniform build system. – Providing quality project information. – Providing guidelines and best practices for development. – Allowing transparent migration to new features.

● See: https://maven.apache.org/what-is-maven.html

https://maven.apache.org/what-is-maven.html

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Features

● Major features include the following: – Uniform build system – Dependency management – Distribution publication – Reporting and website creation

● See: Feature Summary https://maven.apache.org/maven-features.html

https://maven.apache.org/maven-features.html

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Characteristics (1)

● Convention over configuration – E.g., defines a standard project directory layout.

● Defines project lifecycles and lifecycle phases ● Declarative ● Modular and extensible architecture

– All of its functionality is provided by plugins.

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Characteristics (2) ● Although it is used mainly for Java projects, can be also used for other

programming languages, such as: – C/C++:

● nar-maven-plugin https://maven-nar.github.io/ https://github.com/maven-nar/nar-maven-plugin

● Native Maven Plugin https://www.mojohaus.org/maven-native/native-maven-plugin/ https://github.com/mojohaus/maven-native

– Kotlin: ● kotlin-maven-plugin https://kotlinlang.org/docs/reference/using-maven.html

– Scala: ● scala-maven-plugin http://davidb.github.io/scala-maven-plugin/

https://github.com/davidB/scala-maven-plugin

https://maven-nar.github.io/ https://github.com/maven-nar/nar-maven-plugin https://www.mojohaus.org/maven-native/native-maven-plugin/ https://github.com/mojohaus/maven-native https://kotlinlang.org/docs/reference/using-maven.html http://davidb.github.io/scala-maven-plugin/ https://github.com/davidB/scala-maven-plugin

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Development ● Written in Java ● Free and open source software

– Distributed under the Apache License 2.0. ● The current stable version is 3.6.3 (released on

November 25, 2019) – See: Maven Releases History

https://maven.apache.org/docs/history.html ● The next version will be 3.7 ● Repository: https://github.com/apache/maven

https://maven.apache.org/docs/history.html https://github.com/apache/maven

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Installation

● Requires a JDK to be installed, not just a JRE! – JDK 7 or later is required.

● The JAVA_HOME environment variable must be set properly!

● Download the latest version of Apache Maven from here: https://maven.apache.org/download.html

● Installation consists of unpacking an archive and setting the PATH environment variable.

https://maven.apache.org/download.html

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Installation (Linux) (1)

● If unpacked in the directory /opt/apache- maven-3.6.3, set the PATH environment variable as shown: – export PATH=/opt/apache-maven-3.6.3/bin:$PATH

● Hint: add the above command to the /etc/profile.d/maven.sh file in order to be automatically executed.

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Installation (Linux) (2)

● Alternatively, Apache Maven can be installed via the SDKMAN! tool, executing the following command: sdk install maven

● For the installation instructions of SDKMAN! see: https://sdkman.io/install

https://sdkman.io/install

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Installation (Windows)

● If unpacked in the directory C:\Program Files\apache-maven-3.6.3 – Add the C:\Program Files\apache-maven- 3.6.3\bin directory to the PATH environment variable.

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Verifying Successful Installation

● Execute one of the following two equivalent commands in the command line: – mvn –version – mvn -v

● If the installation was successful, you should see the following output:

Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f) Maven home: /home/jeszy/.sdkman/candidates/maven/current Java version: 15.0.2, vendor: Oracle Corporation, runtime: /home/jeszy/.sdkman/candidates/java/15.0.2-open Default locale: hu_HU, platform encoding: UTF-8 OS name: "linux", version: "5.1.5-050105-generic", arch: "amd64", family: "unix"

Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f) Maven home: /home/jeszy/.sdkman/candidates/maven/current Java version: 15.0.2, vendor: Oracle Corporation, runtime: /home/jeszy/.sdkman/candidates/java/15.0.2-open Default locale: hu_HU, platform encoding: UTF-8 OS name: "linux", version: "5.1.5-050105-generic", arch: "amd64", family: "unix"

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IDE Integration (1) ● Eclipse: m2eclipse https://www.eclipse.org/m2e/

– Update site: https://download.eclipse.org/technology/m2e/releases/latest/

– The Indigo release of the Eclipse IDE for Java Developers is shipped together with m2eclipse (no installation is required).

● IntelliJ IDEA: Provides built-in Apache Maven support. – See: https://www.jetbrains.com/help/idea/maven.html

● Netbeans: Provides built-in Apache Maven support since version 6.7. – See: http://wiki.netbeans.org/Maven

https://www.eclipse.org/m2e/ https://download.eclipse.org/technology/m2e/releases/latest/ https://www.jetbrains.com/help/idea/maven.html http://wiki.netbeans.org/Maven

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IDE Integration (2)

● Visual Studio Code: Maven support is provided by the Maven for Java extension. – See:

● Maven for Java https://marketplace.visualstudio.com/items?itemName=vs cjava.vscode-maven

● Java Project Management in VS Code – Maven https://code.visualstudio.com/docs/java/java-project#_ma ven

https://marketplace.visualstudio.com/items?itemName=vscjava.vscode-maven https://marketplace.visualstudio.com/items?itemName=vscjava.vscode-maven https://code.visualstudio.com/docs/java/java-project#_maven https://code.visualstudio.com/docs/java/java-project#_maven

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Further Information ● Official documentation: https://maven.apache.org/guides/ ● Free electronic books (licenc: Creative Commons BY-

NC-ND): https://www.sonatype.com/resources/ebooks – Maven by Example

https://github.com/sonatype/maven-example-en – Maven: The Complete Reference

https://github.com/sonatype/maven-reference-en – Repository Management with Nexus

https://github.com/sonatype/nexus-book ● Mailing lists: https://maven.apache.org/mailing-lists.html

https://maven.apache.org/guides/ https://www.sonatype.com/resources/ebooks https://github.com/sonatype/maven-example-en https://github.com/sonatype/maven-reference-en https://github.com/sonatype/nexus-book https://maven.apache.org/mailing-lists.html

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Standard Directory Layout (1)

● Standard directory layout for projects: – Introduction to the Standard Directory Layout

https://maven.apache.org/guides/introduction/introd uction-to-the-standard-directory-layout.html

https://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html https://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html

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Standard Directory Layout (2)

resources/

project/

src/

main/

java/

resources/

test/

java/

pom.xml

site/

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Usage (1)

● Execute the mvn --help or mvn -h command to display usage information and available command line options.

● Apache Maven accepts lifecycle phases (e.g., mvn package) and plugin goals (e.g., mvn site:run) as command line arguments. – Multiple number of such command line arguments can be

supplied. – Further options can be passed as system properties in the

form -Dname=value

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Usage (2)

● Plugin goals can be specified in the form groupId:artifactId:version:goal – This syntax is required when a specific version of

the plugin must be used or Apache Maven does not associate a prefix with the plugin.

– Example: mvn org.codehaus.mojo:versions-maven- plugin:2.8.1:help

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settings.xml (1)

● A configuration file that stores project independent settings. – The $M2_HOME/conf/settings.xml file

provides global setting for all users. – Users can place an own settings.xml file in

the .m2 directory of their home directory to override global settings.

● On Linux systems the path of this file is ~/.m2/settings.xml.

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settings.xml (2)

● Reference: https://maven.apache.org/ref/current/maven-set tings/settings.html

● XML schema: http://maven.apache.org/xsd/settings-1.1.0.xsd

https://maven.apache.org/ref/current/maven-settings/settings.html https://maven.apache.org/ref/current/maven-settings/settings.html http://maven.apache.org/xsd/settings-1.1.0.xsd

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settings.xml (3)

● The effective-settings goal of the Maven Help Plugin displays the current configuration settings. – The mvn help:effective-settings command outputs a