How To Create A Java Project With Maven

1. Create a Project from Maven Template

In a command prompt (Windows), navigate to the folder you want to store the project. Issue following commands :

mvn archetype:generate -DgroupId={project-packaging} -DartifactId={project-name} -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

This tell Maven to create a Java project from “maven-archetype-quickstart” template. If you ignore thearchetypeArtifactId argument, a list of the templates will be listed for you to choose.

For example,

mvn archetype:generate -DgroupId=com.ash -DartifactId=First -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'archetype'.
[INFO] -------------------------------------------------------------------
[INFO] Building Maven Default Project
[INFO]    task-segment: [archetype:generate] (aggregator-style)
[INFO] -------------------------------------------------------------------
[INFO] Preparing archetype:generate
[INFO] No goals needed for project - skipping
[INFO] [archetype:generate {execution: default-cli}]
[INFO] Generating project in Batch mode
[INFO] -------------------------------------------------------------------
[INFO] Using following parameters for creating project 
 from Old (1.x) Archetype: maven-archetype-quickstart:1.0
[INFO] -------------------------------------------------------------------
[INFO] Parameter: groupId, Value: com.ash
[INFO] Parameter: packageName, Value: com.ash
[INFO] Parameter: package, Value: com.ash
[INFO] Parameter: artifactId, Value First
[INFO] Parameter: basedir, Value: C:\MVN
[INFO] Parameter: version, Value: 1.0-SNAPSHOT
[INFO] project created from Old (1.x) Archetype in dir: C:\MVN\consumerBanking
[INFO] ------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------
[INFO] Total time: 14 seconds
[INFO] Finished at: Tue Jul 10 15:38:58 IST 2012
[INFO] Final Memory: 21M/124M
[INFO] 

2. Maven Directory Layout

Maven created following standard directory layout.

NumberGenerator
   |-src
   |---main
   |-----java
   |-------com
   |---------ash
   |-----------App.java
   |---test
   |-----java
   |-------com
   |---------ash
   |-----------AppTest.java
   |-pom.xml

What we learnt in Project Creation chapter is how to create a Java application using Maven. Now we'll see how to build and test the application.

Go to C:/MVN directory where you've created your java application. Open First folder.You will see the POM.xml file with following contents.

<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.ash</groupId>
      <artifactId>First</artifactId>
      <version>1.0</version>
      <dependencies>
         <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
         </dependency>
      </dependencies>  
</project>

Here you can see, Maven already added Junit as test framework. By default Maven adds a source fileApp.java and a test file AppTest.java in its default directory structure discussed in previous chapter.

Let's open command console, go the C:\MVN\consumerBanking directory and execute the following mvncommand.

C:\MVN\First>mvn clean package

Maven will start building the project.

[INFO] Scanning for projects...
[INFO] -------------------------------------------------------------------
[INFO] Building consumerBanking
[INFO]    task-segment: [clean, package]
[INFO] -------------------------------------------------------------------
[INFO] [clean:clean {execution: default-clean}]
[INFO] Deleting directory C:\MVN\first\target
[INFO] [resources:resources {execution: default-resources}]
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\first\src\main\
resources
[INFO] [compiler:compile {execution: default-compile}]
[INFO] Compiling 1 source file to C:\MVN\first\target\classes
[INFO] [resources:testResources {execution: default-testResources}]
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\first\src\test\
resources
[INFO] [compiler:testCompile {execution: default-testCompile}]
[INFO] Compiling 1 source file to C:\MVN\first\target\test-classes
[INFO] [surefire:test {execution: default-test}]
[INFO] Surefire report directory: C:\MVN\first\target\
surefire-reports
-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.companyname.bank.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.027 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

[INFO] [jar:jar {execution: default-jar}]
[INFO] Building jar: C:\MVN\first\target\
consumerBanking-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2 seconds
[INFO] Finished at: Tue Jul 10 16:52:18 IST 2012
[INFO] Final Memory: 16M/89M
[INFO] ------------------------------------------------------------------------

You've built your project and created final jar file, following are the key learning concepts

• We give maven two goals, first to clean the target directory (clean) and then package the project build output as jar(package).
• Packaged jar is available in first\target folder as first-1.0-SNAPSHOT.jar.
• Test reports are available in first\target\surefire-reports folder.
• Maven compiled source code file(s) and then test source code file(s).
• Then Maven run the test cases.
• Finally Maven created the package.

Now open command console, go the C:\MVN\first\target\classes directory and execute the following java command.

C:\MVN\consumerBanking\target\classes>java com.ash.App

You will see the result

Hello World!

Adding Java Source Files

Let's see how we can add additional Java files in our project. Open C:\MVN\first\src\main\java\com\companyname\bank folder, create Util class in it as Util.java.

package com.ash.bank;

public class Util 
{
   public static void printMessage(String message){
    System.out.println(message);
   }
}

Update App class to use Util class.

package com.ash.bank;

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

Now open command console, go the C:\MVN\consumerBanking directory and execute the following mvncommand.

C:\MVN\first>mvn clean compile

After Maven build is successful, go the C:\MVN\consumerBanking\target\classes directory and execute the following java command.

C:\MVN\first\target\classes>java -cp com.ash.App

You will see the result

Hello World!

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