Maven command line usage

Figure 260. CLI example Slide presentation 
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 261. Supplementary MI Maven archetypes Slide presentation

❶

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

❷

Use a text editor creating (or adding) the following content in ~/.m2/settings.xml. Any text editor like (vim, nano, emacs, IntelliJ,...) will do: 

<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>archetypeMI</id>
          <name>Supplementary MI archetypes and artifacts</name>
          <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>

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


After editing you should test your configuration by creating a dummy project (copy and paste to a terminal window):

Figure 262. CLI archetype test Slide presentation 
  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=2.1
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
      ...
[INFO] BUILD SUCCESS ...

Figure 263. CLI archetype details Slide presentation

Defining archetype and project details:

mvn --batch-mode ❶ -e archetype:generate ❷ \
                                              \
 -DarchetypeGroupId=de.hdm_stuttgart.mi \ ❸
 -DarchetypeArtifactId=mi-maven-archetype-quickstart \
 -DarchetypeVersion=2.1 \
                        \
 -DgroupId=de.hdm_stuttgart.mi.sd1 ❹ \
 -DartifactId=first  \
 -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

archetypeGroupId, archetypeArtifactId and archetypeVersion uniquely identify an archetype.

mi-maven-archetype-quickstart denotes one of several available archetypes.

❹

Likewise groupId, artifactId and version are intended to uniquely define a project being generated. Moreover the groupId property defines the project's default base package to be explained in Objects and Classes.


Figure 264. Generated project layout Slide presentation 
> cd first        # Enter project directory
> find . -type f  # Search recursively for files
./.gitignore ❶
./src/main/java/de/hdm_stuttgart/mi/sd1/App.java ❷
./pom.xml ❸

❶

Exclude specific files from version git based control.

❷

Java™ source file containing an executable main() class.

❸

The Project Object Model file defining build rules.


Figure 265. Maven compile Slide presentation 
> mvn compile
[INFO] Scanning for projects...
       ...
[INFO] Building first 0.9
   ...
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /ma/goik/first/target/classes
[INFO] --------------------------------------------------------
[INFO] BUILD SUCCESS

Figure 266. Compilation file view Slide presentation 
> find target/classes -type f
./target/classes/de/hdm_stuttgart/mi/sd1/App.class
...

Figure 267. Execution Slide presentation 
> cd target/classes ❶
> java de.hdm_stuttgart.mi.sd1.App ❷
Hi there, let's have
fun learning Java! ❸

❶

Change to base directory containing compiled Java™ classes.

❷

Application execution. Note:

Our App class is being prefixed by the package name de.hdm_stuttgart.mi.sd1 defined by the groupId parameter in Figure 263, “CLI archetype details ”.

❸

The expected output result.

Note

Executing this particular class requires a configuration in our project's pom.xml file: 

...
<archive>
  <manifest>
    <mainClass>de.hdm_stuttgart.mi.sd1.test.ShowReachedPoints</mainClass>
  </manifest>
</archive> ...

Figure 268. Maven package Slide presentation 
> mvn package
...
 T E S T S
...
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
   ...
[INFO] Building jar: /ma/goik/first/target/first-0.9.jar
...
[INFO] Replacing /ma/goik/first/target/first-0.9.jar with 
         /ma/goik/first/target/first-0.9-shaded.jar
...
[INFO] BUILD SUCCESS

Figure 269. Executing Java™ archive first-0.9.jar Slide presentation 
java -jar target/first-0.9.jar
Hi there, let's have
fun learning Java!

Remark: This will execute HelloWorld.class being contained in first-0.9.jar.


exercise No. 112

Details on execution

Q:

In Figure 269, “Executing Java™ archive first-0.9.jar ” we saw successful execution of: 

java -jar target/first-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 first-0.9.jar file to examine the contained file META-INF/MANIFEST.MF.

A:

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 first-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 270. Maven javadoc:javadoc Slide presentation 
> mvn javadoc:javadoc
[INFO] Scanning for projects...
...
Generating /ma/goik/First/target/site/apidocs/allclasses-noframe.html...
Generating /ma/goik/First/target/site/apidocs/index.html...
Generating /ma/goik/First/target/site/apidocs/overview-summary.html...
Generating /ma/goik/First/target/site/apidocs/help-doc.html...

See e.g. class String documentation.


Figure 271. Maven clean Slide presentation 
> mvn clean
...
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ first ---
[INFO] Deleting /ma/goik/first/target
[INFO] ------------------------------------------------------------------------
[

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