I changed this: hello world

Creating files in the repo

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

Printing "Hello World!"

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

// updated 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/

If you need help at any time

Running mvn --help will display the maven help menu

-The emojis for git are amazing!

#This is just a test BL Taken from http://www.tutorialspoint.com/maven/maven_pom.htm #POM POM stands for Project Object Model. It is fundamental Unit of Work in Maven. It is an XML file. It always resides in the base directory of the project as pom.xml.

The POM contains information about the project and various configuration detail used by Maven to build the project(s).

POM also contains the goals and plugins. While executing a task or goal, Maven looks for the POM in the current directory. It reads the POM, gets the needed configuration information, then executes the goal. Some of the configuration that can be specified in the POM are following:

• project dependencies

• plugins

• goals

• build profiles

• project version

• developers

• mailing list

Before creating a POM, we should first decide the project group (groupId), its name(artifactId) and its version as these attributes help in uniquely identifying the project in repository.

#Example POM:

<project xmlns="http://maven.apache.org/POM/4.0.0"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
   http://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.companyname.project-group</groupId>
   <artifactId>project</artifactId>
   <version>1.0</version>
</project>

It should be noted that there should be a single POM file for each project.

• All POM files require the project element and three mandatory fields:

  • groupId,
  • artifactId,
  • version.

• Projects notation in repository is groupId:artifactId:version.

• Root element of POM.xml is project and it has three major sub-nodes :

Node	Description
groupId	This is an Id of project's group. This is generally unique amongst an organization or a project. For example, a banking group com.company.bank has all bank related projects.
artifactId	This is an Id of the project.This is generally name of the project. For example, consumer-banking. Along with the groupId, the artifactId defines the artifact's location within the repository.
version	This is the version of the project.Along with the groupId, It is used within an artifact's repository to separate versions from each other. For example: com.company.bank:consumer-banking:1.0 com.company.bank:consumer-banking:1.1.