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.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false
Now, to print "Hello World!", type either...
cd my-app
mvn compile
java -cp target/classes com.mycompany.app.App
or...
cd my-app
mvn package
java -cp target/my-app-1.0-SNAPSHOT.jar com.mycompany.app.App
Running mvn clean will get us back to only the source Java and the pom.xml:
murphy:my-app pdurbin$ mvn clean --quiet
murphy:my-app pdurbin$ ack -a -f
pom.xml
src/main/java/com/mycompany/app/App.java
src/test/java/com/mycompany/app/AppTest.java
Running mvn compile produces a class file:
murphy:my-app pdurbin$ mvn compile --quiet
murphy:my-app pdurbin$ ack -a -f
pom.xml
src/main/java/com/mycompany/app/App.java
src/test/java/com/mycompany/app/AppTest.java
target/classes/com/mycompany/app/App.class
murphy:my-app pdurbin$
murphy:my-app pdurbin$ java -cp target/classes com.mycompany.app.App
Hello World!
Running mvn package does a compile and creates the target directory, including a jar:
murphy:my-app pdurbin$ mvn clean --quiet
murphy:my-app pdurbin$ mvn package > /dev/null
murphy:my-app pdurbin$ ack -a -f
pom.xml
src/main/java/com/mycompany/app/App.java
src/test/java/com/mycompany/app/AppTest.java
target/classes/com/mycompany/app/App.class
target/maven-archiver/pom.properties
target/my-app-1.0-SNAPSHOT.jar
target/surefire-reports/com.mycompany.app.AppTest.txt
target/surefire-reports/TEST-com.mycompany.app.AppTest.xml
target/test-classes/com/mycompany/app/AppTest.class
murphy:my-app pdurbin$
murphy:my-app pdurbin$ java -cp target/my-app-1.0-SNAPSHOT.jar com.mycompany.app.App
Hello World!
Running mvn clean compile exec:java requires http://mojo.codehaus.org/exec-maven-plugin/
Running java -jar target/my-app-1.0-SNAPSHOT.jar requires http://maven.apache.org/plugins/maven-shade-plugin/