Important Notes for Developers 1.Version Management

The pipeline automatically increments the pom.xml version when you push changes to the dev or master branches. Example: If the current version is 1.0.0 and you push a commit, the pipeline updates it to 1.0.1.

2.Syncing Your Local Repository

After a pipeline run, your local repository may be out of sync because the pom.xml file is updated and committed by the workflow. Always run the following command before making new changes:

git pull origin dev # For the dev branch git pull origin master # For the master branch This ensures you have the latest version of the pom.xml and other files.

3.Triggering the Pipeline

The pipeline is triggered automatically when you push to the dev or master branches.

A simple, minimal Maven example: hello world

To create the files in this git repo we've already run mvn archetype:generate from http://maven.apache.org/guides/getting-started/maven-in-five-minutes.html

mvn archetype:generate -DgroupId=com.myapp.app -DartifactId=myapp -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4 -DinteractiveMode=false

Now, to print "Hello World!", type either...

cd myapp
mvn compile
java -cp target/classes com.myapp.app.App

or...

cd myapp
mvn package
java -cp target/myapp-1.0-SNAPSHOT.jar com.myapp.app.App

Running mvn clean will get us back to only the source Java and the pom.xml:

murphy:myapp pdurbin$ mvn clean --quiet
murphy:myapp pdurbin$ ack -a -f
pom.xml
src/main/java/com/myapp/app/App.java
src/test/java/com/myapp/app/AppTest.java

Running mvn compile produces a class file:

murphy:myapp pdurbin$ mvn compile --quiet
murphy:myapp pdurbin$ ack -a -f
pom.xml
src/main/java/com/myapp/app/App.java
src/test/java/com/myapp/app/AppTest.java
target/classes/com/myapp/app/App.class
murphy:myapp pdurbin$ 
murphy:myapp pdurbin$ java -cp target/classes com.myapp.app.App
Hello World!

Running mvn package does a compile and creates the target directory, including a jar:

murphy:myapp pdurbin$ mvn clean --quiet
murphy:myapp pdurbin$ mvn package > /dev/null
murphy:myapp pdurbin$ ack -a -f
pom.xml
src/main/java/com/myapp/app/App.java
src/test/java/com/myapp/app/AppTest.java
target/classes/com/myapp/app/App.class
target/maven-archiver/pom.properties
target/myapp-1.0-SNAPSHOT.jar
target/surefire-reports/com.myapp.app.AppTest.txt
target/surefire-reports/TEST-com.myapp.app.AppTest.xml
target/test-classes/com/myapp/app/AppTest.class
murphy:myapp pdurbin$ 
murphy:myapp pdurbin$ java -cp target/myapp-1.0-SNAPSHOT.jar com.myapp.app.App
Hello World!

Running mvn clean compile exec:java requires https://www.mojohaus.org/exec-maven-plugin/

Running java -jar target/myapp-1.0-SNAPSHOT.jar requires http://maven.apache.org/plugins/maven-shade-plugin/

Runnable Jar:

JAR Plugin The Maven’s jar plugin will create jar file and we need to define the main class that will get executed when we run the jar file.

<plugin>
  <artifactId>maven-jar-plugin</artifactId>
  <version>3.0.2</version>
  <configuration>
    <archive>
      <manifest>
        <addClasspath>true</addClasspath>
        <mainClass>com.myapp.App</mainClass>
      </manifest>
    </archive>
  </configuration>
</plugin>

Folder tree before package:

├── pom.xml
└── src
    ├── main
    │   └── java
    │       └── com
    │           └── myapp
    │               └── app
    │                   └── App.java
    └── test
        └── java
            └── com
                └── myapp
                    └── app
                        └── AppTest.java

Folder tree after package:

.
├── pom.xml
├── src
│   ├── main
│   │   └── java
│   │       └── com
│   │           └── myapp
│   │               └── app
│   │                   └── App.java
│   └── test
│       └── java
│           └── com
│               └── myapp
│                   └── app
│                       └── AppTest.java
└── target
    ├── classes
    │   └── com
    │       └── myapp
    │           └── app
    │               └── App.class
    ├── generated-sources
    │   └── annotations
    ├── generated-test-sources
    │   └── test-annotations
    ├── maven-archiver
    │   └── pom.properties
    ├── maven-status
    │   └── maven-compiler-plugin
    │       ├── compile
    │       │   └── default-compile
    │       │       ├── createdFiles.lst
    │       │       └── inputFiles.lst
    │       └── testCompile
    │           └── default-testCompile
    │               ├── createdFiles.lst
    │               └── inputFiles.lst
    ├── myapp-1.0-SNAPSHOT.jar
    ├── surefire-reports
    │   ├── com.myapp.app.AppTest.txt
    │   └── TEST-com.myapp.app.AppTest.xml
    └── test-classes
        └── com
            └── myapp
                └── app
                    └── AppTest.class