Hello Maven!

The easiest way to get started with a Maven project is to use the generate goal of the archetype plugin to generate a simple Maven project. Maven archetypes are discussed in detail in Chapter 3, Maven Archetypes, and plugins are covered in Chapter 4, Maven Plugins.

Let's start with a simple example:

$ mvn archetype:generate 
 -DgroupId=com.packt.samples 
 -DartifactId=com.packt.samples.archetype 
 -Dversion=1.0.0 
 -DinteractiveMode=false

This command will invoke the generate goal of the Maven archetype plugin to create a simple Java project. You will see that the following project structure is created with a sample POM file. The name of the root or the base directory is derived from the value of the artifactId parameter:

com.packt.samples.archetype 
               |-pom.xml
               |-src
               |-main/java/com/packt/samples/App.java
               |-test/java/com/packt/samples/AppTest.java    

The sample POM file will only have a dependency to the junit JAR file with test as the scope:

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.packt.samples</groupId>
  <artifactId>com.packt.samples.archetype</artifactId>
  <packaging>jar</packaging>
  <version>1.0.0</version>
  <name>com.packt.samples.archetype</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

The generated App.java class will have the following template code. The name of the package is derived from the provided groupId parameter. If you want to have a different value as the package name, then you need to pass this value in the command itself as -Dpackage=com.packt.samples.application:

package com.packt.samples;

/**
 * Hello world!
 *
 */
public class App 
{
    public static void main( String[] args )
    {
        System.out.println( "Hello World!" );
    }
}

To build the sample project, run the following command from the com.packt.samples.archetype directory, where the pom.xml file exists:

$ mvn clean install