Maven command line usage -

Maven command line usage

Figure 293. Using the MI Sd1 project template

Download file mavenTemplate.zip from here.
Extract mavenTemplate.zip to folder template.
Optional: Edit template/pom.xml reflecting your project needs i.e. <groupId> and related.
Optional: Import your project in Intellij IDEA.

Figure 294. CLI example

> mvn --batch-mode -e archetype:generate \
-DgroupId=de.hdm_stuttgart.mi.sd1 -DartifactId=second -Dversion=0.9 \
-DarchetypeGroupId=org.apache.maven.archetypes -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4

[INFO] Scanning for projects...
      ...
[INFO] BUILD SUCCESS ...

See artifact reference.

The MI department provides modified archetypes supporting more current versions of unit testing software. These are being provided by a Maven repository server:

Figure 295. Supplementary MI Maven archetypes

MI nexus repository server

Configuration:

mkdir -p ~/.m2 ❶
nano ~/.m2/settings.xml ❷

❶

Create an empty .m2 Maven configuration and caching related directory below your home directory ~. The -p option avoids an error message in case ~/.m2 already exists.

❷

Use a text editor like nano, vim, emacs, IntelliJ,... for creating the following (presumably new) file ~/.m2/settings.xml:

<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>
    <profile>
      <id>development</id>
      <repositories>
        <repository>
          <id>miSupplementaryMavenStuff</id>
          <name>Supplementary MI archetypes and artifacts</name>

          <!-- The actual »payload« referring to the MI Maven server hosting additional archetypes and artifacts -->
          <url>https://maven.mi.hdm-stuttgart.de/nexus/repository/mi-maven</url>

          <releases><enabled>true</enabled></releases>
          <snapshots><enabled>true</enabled></snapshots>
        </repository>
      </repositories>
    </profile>
  </profiles>

  <activeProfiles>
    <activeProfile>development</activeProfile>
  </activeProfiles>

</settings>

Note

https://maven.mi.hdm-stuttgart.de/nexus/repository/mi-maven refers to a Sonatype Nexus repository manager instance hosting supplementary Maven archetypes and artifacts.

Figure 296. CLI testing mi-maven-archetype-quickstart

> mvn --batch-mode -e archetype:generate \
  -DgroupId=de.hdm_stuttgart.mi.sd1 -DartifactId=second -Dversion=0.9 \
  -DarchetypeGroupId=de.hdm_stuttgart.mi -DarchetypeArtifactId=mi-maven-archetype-quickstart -DarchetypeVersion=2.5
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
      ...
[INFO] BUILD SUCCESS ...

Figure 297. CLI archetype details

> mvn --batch-mode ❶ -e archetype:generate ❷ \
                                              \
 -DarchetypeGroupId=de.hdm_stuttgart.mi \ ❸
 -DarchetypeArtifactId=mi-maven-archetype-quickstart \
 -DarchetypeVersion=2.5 \
                        \
 -DgroupId=de.hdm_stuttgart.mi.sd1 ❹ \
 -DartifactId=second  \
 -Dversion=0.9

❶	During project generation Maven shall work in batch mode not asking for user input.
❷	Create a Maven project using an archetype being specified by ❸.
❸	Our desired archetype is being addressed by its three »coordinates« on the MI Maven repository server: archetypeGroupId de.hdm_stuttgart.mi, typically referring to the hosting institution. archetypeArtifactId mi-maven-archetype-quickstart, denoting a piece of software within the hosting institution. archetypeVersion 2.5, identifying a specific version of the software in question.
❹	Likewise the remaining three parameter uniquely define our own software product's Maven »coordinates«: groupId. This value also defines the projects base package name as being explained in the section called “Packages”: package de.hdm_stuttgart.mi.sd1; ... public class ... Note The Java™ syntax disallows operator symbols like “-” in `package` names. Since by default the package name is being derived from our groupId definition we cannot not use “-” here either unless manually correcting the package name. For this reason the current example features `de.hdm_stuttgart.mi.sd1` rather than `de.hdm-stuttgart.mi.sd1`. artifactId The project's unique name within the groupId's realm. version The project's unique version within the artifactId's realm.

Figure 298. Generated project layout

> tree -a
├── dependency-reduced-pom.xml
├── .gitignore
├── pom.xml ❶
├── Readme.md
└── src
    ├── main
    │   ├── java
    │   │   └── de
    │   │       └── hdm_stuttgart
    │   │           └── mi
    │   │               └── sd1
    │   │                   ├── App.java ❷
    │   │                   ├── HighlightSample.java
    │   │                   └── Statistics.java
    │   └── resources
    │       └── log4j2.xml
    └── test
        └── java
            └── de
                └── hdm_stuttgart
                    └── mi
                        └── sd1
                            └── AppTest.java

❶	The Project Object Model file defining build rules.
❷	Java™ source file containing an executable `main()` class.

exercise No. 117

DNS inflicted groupId / package names clashes

Regarding the extended explanations of Figure 297, “CLI archetype details ” we consider two different organisations https://hdm-stuttgart.de and https://hdm_stuttgart.de. Following the »coordinate« recommendations both organizations would then choose the common conflicting groupId de.hdm_stuttgart leading to possible Maven artifact clashes. May this conflict actually happen?

Tip

Read about valid DNS domain names.

The conflict cannot occur since the underscore is being disallowed in domain names according to the DNS specification. Thus hdm_stuttgart.de is an illegal domain name. Mapping hyphens appearing in domain names to underscores in packages therefore works perfectly.

Figure 299. Maven compile

> mvn compile
[INFO] Scanning for projects...
       ...
[INFO] Building second 0.9
   ...
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /ma/goik/second/target/classes
[INFO] --------------------------------------------------------
[INFO] BUILD SUCCESS

Figure 300. Compilation file view

> tree target/classes
target/classes/
├── de
│   └── hdm_stuttgart
│       └── mi
│           └── sd1
│               ├── App.class
│               ├── HighlightSample.class
│               └── Statistics.class
└── log4j2.xml

Figure 301. Maven package

> mvn package
[INFO] -------------------< de.hdm_stuttgart.mi.sd1:second >-------------------
[INFO] Building second 0.9
...
[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running de.hdm_stuttgart.mi.sd1.AppTest
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.253 s -- in de.hdm_stuttgart.mi.sd1.AppTest
...
[INFO] Building jar: /home/goik/Downloads/second/target/second-0.9.jar
...
[INFO] BUILD SUCCESS

Figure 302. Executing Java™ archive second-0.9.jar

> java -jar target/second-0.9.jar
Hi there, let's have
fun learning Java!

2026-01-11 07:40:33,903 INFO  [main] sd1.App (App.java:27) - The following two statements will log to file A1.log, ...
2026-01-11 07:40:33,905 DEBUG [main] sd1.App (App.java:28) - You may configure 'src/main/resources/log4j2.xml' 
2026-01-11 07:40:33,905 DEBUG [main] sd1.App (App.java:29) - for adapting both console and 'A1.log' file output

Note

Executing this requires defining App.class as main entry point in our project's pom.xml file:

...
<manifestEntries>
   <Main-Class>de.hdm_stuttgart.mi.sd1.App</Main-Class>
   <Multi-Release>true</Multi-Release>
</manifestEntries>
 ...

Remark: This will execute App.class being contained in second-0.9.jar.

exercise No. 118

Details on execution

In Figure 302, “Executing Java™ archive second-0.9.jar ” we saw the execution of:

java -jar target/second-0.9.jar

How does this actually work? There might be multiple executable classes containing main() methods within a given project? How is de/hdm_stuttgart/mi/sd1/App.class being selected for execution?

Tip

Have a closer look on your project's pom.xml. Also unzip your generated second-0.9.jar file to examine the contained META-INF/MANIFEST.MF file.

Our pom.xml defines a single class which must contain a public static void main(String[] args) method:

<project xmlns="http://maven.apache.org/POM/4.0.0" ...>
  <modelVersion>4.0.0</modelVersion>
  ...
    <manifestEntries>
       <Main-Class>de.hdm_stuttgart.mi.sd1.App</Main-Class>
    </manifestEntries>
  ...
</project>

The Maven package processing step wraps this class name into the generated second-0.9.jar archive's manifest file META-INF/MANIFEST.MF:

> cat META-INF/MANIFEST.MF 
Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Created-By: Apache Maven 3.5.2
Built-By: goik
Build-Jdk: 10.0.2
Main-Class: de.hdm_stuttgart.mi.sd1.App

This allows the Java™ runtime to choose the class to be executed.

Figure 303. Maven javadoc:javadoc

> mvn javadoc:javadoc
[INFO] Scanning for projects...
...
Generating /ma/goik/second/target/site/apidocs/allclasses-noframe.html...
Generating /ma/goik/second/target/site/apidocs/index.html...
Generating /ma/goik/second/target/site/apidocs/overview-summary.html...
Generating /ma/goik/second/target/site/apidocs/help-doc.html...

See e.g. class String documentation.

Figure 304. Maven clean

> mvn clean
...
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ second ---
[INFO] Deleting /ma/goik/second/target
[INFO] ------------------------------------------------------------------------
[

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