Maven - Quick Guide


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Maven - Overview

What is Maven?

Maven is a project management and comprehension tool. Maven provides developers a complete build lifecycle framework. Development team can automate the project's build infrastructure in almost no time as Maven uses a standard directory layout and a default build lifecycle.

In case of multiple development teams environment, Maven can set-up the way to work as per standards in a very short time. As most of the project setups are simple and reusable, Maven makes life of developer easy while creating reports, checks, build and testing automation setups.

Maven provides developers ways to manage following:

  • Builds

  • Documentation

  • Reporting

  • Dependencies

  • SCMs

  • Releases

  • Distribution

  • mailing list

To summarize, Maven simplifies and standardizes the project build process. It handles compilation, distribution, documentation, team collaboration and other tasks seamlessly. Maven increases reusability and takes care of most of build related tasks.

Maven History

Maven was originally designed to simplify building processes in Jakarta Turbine project. There were several projects and each project contained slightly different ANT build files. JARs were checked into CVS.

Apache group then developed Maven which can build multiple projects together, publish projects information, deploy projects, share JARs across several projects and help in collaboration of teams.

Maven Objective

Maven primary goal is to provide developer

  • A comprehensive model for projects which is reusable, maintainable, and easier to comprehend.

  • plugins or tools that interact with this declarative model.

Maven project structure and contents are declared in an xml file, pom.xml referred as Project Object Model (POM), which is the fundamental unit of the entire Maven system. Refer to Maven POM section for more detail.

Convention over Configuration

Maven uses Convention over Configuration which means developers are not required to create build process themselves.

Developers do not have to mention each and every configuration detail. Maven provides sensible default behavior for projects. When a Maven project is created, Maven creates default project structure. Developer is only required to place files accordingly and he/she need not to define any configuration in pom.xml.

As an example, following table shows the default values for project source code files, resource files and other configurations. Assuming, ${basedir} denotes the project location:

Item Default
source code ${basedir}/src/main/java
resources ${basedir}/src/main/resources
Tests ${basedir}/src/test
distributable JAR ${basedir}/target
Complied byte code ${basedir}/target/classes

In order to build the project, Maven provides developers options to mention life-cycle goals and project dependencies (that rely on Maven pluging capabilities and on its default conventions). Much of the project management and build related tasks are maintained by Maven plugins.

Developers can build any given Maven project without need to understand how the individual plugins work. Refer to Maven Plug-ins section for more detail.

Maven Environment Setup

Maven is Java based tool, so the very first requirement is to have JDK installed on your machine.

System Requirement

JDK 1.5 or above.
Memory no minimum requirement.
Disk Space no minimum requirement.
Operating System no minimum requirement.

Step 1 - verify Java installation on your machine

Now open console and execute the following java command.

OS TaskCommand
Windows Open Command Console c:\> java -version
Linux Open Command Terminal $ java -version
Mac Open Terminal machine:~ joseph$ java -version

Let's verify the output for all the operating systems:

OS Output
Windows java version "1.7.0_75"

Java(TM) SE Runtime Environment (build 1.7.0_75-b13)

Java HotSpot(TM) Client VM (build 24.75-b04, mixed mode, sharing)

Linux java version "1.7.0_75"

Java(TM) SE Runtime Environment (build 1.7.0_75-b13)

Java HotSpot(TM) Client VM (build 24.75-b04, mixed mode, sharing)

Mac java version "1.7.0_75"

Java(TM) SE Runtime Environment (build 1.7.0_75-b13)

Java HotSpot(TM)64-Bit Server VM (build 24.75-b04, mixed mode, sharing)

If you do not have Java installed, install the Java Software Development Kit (SDK) from http://www.oracle.com/technetwork/java/javase/downloads/index.html. We are assuming Java 1.7.0_75 as installed version for this tutorial.

Step 2: Set JAVA environment

Set the JAVA_HOME environment variable to point to the base directory location where Java is installed on your machine. For example

OS Output
Windows Set the environment variable JAVA_HOME to C:\Program Files\Java\jdk1.7.0_75
Linux export JAVA_HOME=/usr/local/java-current
Mac export JAVA_HOME=/Library/Java/Home

Append Java compiler location to System Path.

OS Output
Windows Append the string ;C:\Program Files\Java\jdk1.7.0_75\bin to the end of the system variable, Path.
Linux export PATH=$PATH:$JAVA_HOME/bin/
Mac not required

Verify Java Installation using java -version command explained above.

Step 3: Download Maven archive

Download Maven 3.3.3 from http://maven.apache.org/download.cgi

OS Archive name
Windows apache-maven-3.3.3-bin.zip
Linux apache-maven-3.3.3-bin.tar.gz
Mac apache-maven-3.3.3-bin.tar.gz

Step 4: Extract the Maven archive

Extract the archive, to the directory you wish to install Maven 3.3.3. The subdirectory apache-maven-3.3.3 will be created from the archive.

OS Location (can be different based on your installation)
Windows C:\Program Files\Apache Software Foundation\apache-maven-3.3.3
Linux /usr/local/apache-maven
Mac /usr/local/apache-maven

Step 5: Set Maven environment variables

Add M2_HOME, M2, MAVEN_OPTS to environment variables.

OSOutput
Windows Set the environment variables using system properties.

M2_HOME=C:\Program Files\Apache Software Foundation\apache-maven-3.3.3

M2=%M2_HOME%\bin

MAVEN_OPTS=-Xms256m -Xmx512m

Linux Open command terminal and set environment variables.

export M2_HOME=/usr/local/apache-maven/apache-maven-3.3.3

export M2=$M2_HOME/bin

export MAVEN_OPTS=-Xms256m -Xmx512m

Mac Open command terminal and set environment variables.

export M2_HOME=/usr/local/apache-maven/apache-maven-3.3.3

export M2=$M2_HOME/bin

export MAVEN_OPTS=-Xms256m -Xmx512m

Step 6: Add Maven bin directory location to system path

Now append M2 variable to System Path

OS Output
Windows Append the string ;%M2% to the end of the system variable, Path.
Linux export PATH=$M2:$PATH
Mac export PATH=$M2:$PATH

Step 7: Verify Maven installation

Now open console, execute the following mvn command.

OS Task Command
Windows Open Command Console c:\> mvn --version
Linux Open Command Terminal $ mvn --version
Mac Open Terminal machine:~ joseph$ mvn --version

Finally, verify the output of the above commands, which should be something as follows:

OS Output
Windows Apache Maven 3.3.3 (7994120775791599e205a5524ec3e0dfe41d4a06; 2015-04-22T17:27:37+05:30)

Maven home: C:\Program Files\Apache Software Foundation\apache-maven-3.3.3

Java version: 1.7.0_75, vendor: Oracle Corporation

Java home: C:\Program Files\Java\jdk1.7.0_75\jre

Default locale: en_US, platform encoding: Cp1252

Linux Apache Maven 3.3.3 (7994120775791599e205a5524ec3e0dfe41d4a06; 2015-04-22T17:27:37+05:30)

Maven home: /usr/local/apache-maven/apache-maven-3.3.3

Java version: 1.7.0_75, vendor: Oracle Corporation

Java home: /usr/local/java-current/jdk1.7.0_75/jre

Mac Apache Maven 3.3.3 (7994120775791599e205a5524ec3e0dfe41d4a06; 2015-04-22T17:27:37+05:30)

Maven home: /usr/local/apache-maven/apache-maven-3.3.3

Java version: 1.7.0_75, vendor: Oracle Corporation

Java home: /Library/Java/Home/jdk1.7.0_75/jre

Congratulations! you are now all set to use Apache Maven for your projects.

Maven 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.

Super POM

All POMs inherit from a parent (despite explicitly defined or not). This base POM is known as the Super POM, and contains values inherited by default.

Maven use the effective pom (configuration from super pom plus project configuration) to execute relevant goal. It helps developer to specify minimum configuration detail in his/her pom.xml. Although configurations can be overridden easily.

An easy way to look at the default configurations of the super POM is by running the following command: mvn help:effective-pom

Create a pom.xml in any directory on your computer.Use the content of above mentioned example pom.

In example below, We've created a pom.xml in C:\MVN\project folder.

Now open command console, go the folder containing pom.xml and execute the following mvn command.

C:\MVN\project>mvn help:effective-pom

Maven will start processing and display the effective-pom.

[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'help'.
[INFO] ------------------------------------------------------------------------
[INFO] Building Unnamed - com.companyname.project-group:project-name:jar:1.0
[INFO]    task-segment: [help:effective-pom] (aggregator-style)
[INFO] ------------------------------------------------------------------------
[INFO] [help:effective-pom {execution: default-cli}]
[INFO]

.....

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: < 1 second
[INFO] Finished at: Thu Jul 05 11:41:51 IST 2012
[INFO] Final Memory: 6M/15M
[INFO] ------------------------------------------------------------------------

Effective POM displayed as result in console, after inheritance, interpolation, and profiles are applied.

<!-- ====================================================================== -->
<!--                                                                        -->
<!-- Generated by Maven Help Plugin on 2015-09-26T07:51:19                  -->
<!-- See: http://maven.apache.org/plugins/maven-help-plugin/                -->
<!--                                                                        -->
<!-- ====================================================================== -->

<!-- ====================================================================== -->
<!--                                                                        -->
<!-- Effective POM for project                                              -->
<!-- 'com.companyname.project-group:project:jar:1.0'                        -->
<!--                                                                        -->
<!-- ====================================================================== -->

<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 h
ttp://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>
  <repositories>
    <repository>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
      <id>central</id>
      <name>Central Repository</name>
      <url>https://repo.maven.apache.org/maven2</url>
    </repository>
  </repositories>
  <pluginRepositories>
    <pluginRepository>
      <releases>
        <updatePolicy>never</updatePolicy>
      </releases>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
      <id>central</id>
      <name>Central Repository</name>
      <url>https://repo.maven.apache.org/maven2</url>
    </pluginRepository>
  </pluginRepositories>
  <build>
    <sourceDirectory>C:\MVN\project\src\main\java</sourceDirectory>
    <scriptSourceDirectory>C:\MVN\project\src\main\scripts</scriptSourceDirector
y>
    <testSourceDirectory>C:\MVN\project\src\test\java</testSourceDirectory>
    <outputDirectory>C:\MVN\project\target\classes</outputDirectory>
    <testOutputDirectory>C:\MVN\project\target\test-classes</testOutputDirectory
>
    <resources>
      <resource>
        <directory>C:\MVN\project\src\main\resources</directory>
      </resource>
    </resources>
    <testResources>
      <testResource>
        <directory>C:\MVN\project\src\test\resources</directory>
      </testResource>
    </testResources>
    <directory>C:\MVN\project\target</directory>
    <finalName>project-1.0</finalName>
    <pluginManagement>
      <plugins>
        <plugin>
          <artifactId>maven-antrun-plugin</artifactId>
          <version>1.3</version>
        </plugin>
        <plugin>
          <artifactId>maven-assembly-plugin</artifactId>
          <version>2.2-beta-5</version>
        </plugin>
        <plugin>
          <artifactId>maven-dependency-plugin</artifactId>
          <version>2.8</version>
        </plugin>
        <plugin>
          <artifactId>maven-release-plugin</artifactId>
          <version>2.3.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
    <plugins>
      <plugin>
        <artifactId>maven-clean-plugin</artifactId>
        <version>2.5</version>
        <executions>
          <execution>
            <id>default-clean</id>
            <phase>clean</phase>
            <goals>
              <goal>clean</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-install-plugin</artifactId>
        <version>2.4</version>
        <executions>
          <execution>
            <id>default-install</id>
            <phase>install</phase>
            <goals>
              <goal>install</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-resources-plugin</artifactId>
        <version>2.6</version>
        <executions>
          <execution>
            <id>default-resources</id>
            <phase>process-resources</phase>
            <goals>
              <goal>resources</goal>
            </goals>
          </execution>
          <execution>
            <id>default-testResources</id>
            <phase>process-test-resources</phase>
            <goals>
              <goal>testResources</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>2.12.4</version>
        <executions>
          <execution>
            <id>default-test</id>
            <phase>test</phase>
            <goals>
              <goal>test</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <executions>
          <execution>
            <id>default-testCompile</id>
            <phase>test-compile</phase>
            <goals>
              <goal>testCompile</goal>
            </goals>
          </execution>
          <execution>
            <id>default-compile</id>
            <phase>compile</phase>
            <goals>
              <goal>compile</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-jar-plugin</artifactId>
        <version>2.4</version>
        <executions>
          <execution>
            <id>default-jar</id>
            <phase>package</phase>
            <goals>
              <goal>jar</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-deploy-plugin</artifactId>
        <version>2.7</version>
        <executions>
          <execution>
            <id>default-deploy</id>
            <phase>deploy</phase>
            <goals>
              <goal>deploy</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-site-plugin</artifactId>
        <version>3.3</version>
        <executions>
          <execution>
            <id>default-site</id>
            <phase>site</phase>
            <goals>
              <goal>site</goal>
            </goals>
            <configuration>
              <outputDirectory>C:\MVN\project\target\site</outputDirectory>
              <reportPlugins>
                <reportPlugin>
                  <groupId>org.apache.maven.plugins</groupId>
                  <artifactId>maven-project-info-reports-plugin</artifactId>
                </reportPlugin>
              </reportPlugins>
            </configuration>
          </execution>
          <execution>
            <id>default-deploy</id>
            <phase>site-deploy</phase>
            <goals>
              <goal>deploy</goal>
            </goals>
            <configuration>
              <outputDirectory>C:\MVN\project\target\site</outputDirectory>
              <reportPlugins>
                <reportPlugin>
                  <groupId>org.apache.maven.plugins</groupId>
                  <artifactId>maven-project-info-reports-plugin</artifactId>
                </reportPlugin>
              </reportPlugins>
            </configuration>
          </execution>
        </executions>
        <configuration>
          <outputDirectory>C:\MVN\project\target\site</outputDirectory>
          <reportPlugins>
            <reportPlugin>
              <groupId>org.apache.maven.plugins</groupId>
              <artifactId>maven-project-info-reports-plugin</artifactId>
            </reportPlugin>
          </reportPlugins>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <reporting>
    <outputDirectory>C:\MVN\project\target\site</outputDirectory>
  </reporting>
</project>

In above pom.xml , you can see the default project source folders structure,output directory, plug-ins required, repositories, reporting directory which Maven will be using while executing the desired goals.

Maven pom.xml is also not required to be written manually.

Maven provides numerous archetype plugins to create projects which in order create the project structure and pom.xml

Details are mentioned in Maven plug-ins and Maven Creating Project Sections

Maven Build Life Cycle

What is Build Lifecycle?

A Build Lifecycle is a well defined sequence of phases which define the order in which the goals are to be executed. Here phase represents a stage in life cycle.

As an example, a typical Maven Build Lifecycle consists of following sequence of phases

Phase Handles Description
prepare-resources resource copying Resource copying can be customized in this phase.
compile compilation Source code compilation is done in this phase.
package packaging This phase creates the JAR / WAR package as mentioned in packaging in POM.xml.
installinstallation This phase installs the package in local / remote maven repository.

There are always pre and post phases which can be used to register goals which must run prior to or after a particular phase.

When Maven starts building a project, it steps through a defined sequence of phases and executes goals which are registered with each phase. Maven has following three standard lifecycles:

  • clean

  • default(or build)

  • site

A goal represents a specific task which contributes to the building and managing of a project. It may be bound to zero or more build phases. A goal not bound to any build phase could be executed outside of the build lifecycle by direct invocation.

The order of execution depends on the order in which the goal(s) and the build phase(s) are invoked. For example, consider the command below. The clean and package arguments are build phases while the dependency:copy-dependencies is a goal.

mvn clean dependency:copy-dependencies package

Here the clean phase will be executed first, and then the dependency:copy-dependencies goal will be executed, and finally package phase will be executed.

Clean Lifecycle

When we execute mvn post-clean command, Maven invokes the clean lifecycle consisting of the following phases.

  • pre-clean

  • clean

  • post-clean

Maven clean goal (clean:clean) is bound to the clean phase in the clean lifecycle. Its clean:clean goal deletes the output of a build by deleting the build directory. Thus when mvn clean command executes, Maven deletes the build directory.

We can customize this behavior by mentioning goals in any of the above phases of clean life cycle.

In the following example, We'll attach maven-antrun-plugin:run goal to the pre-clean, clean, and post-clean phases. This will allow us to echo text messages displaying the phases of the clean lifecycle.

We've created a pom.xml in C:\MVN\project folder.

<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.projectgroup</groupId>
<artifactId>project</artifactId>
<version>1.0</version>
<build>
<plugins>
   <plugin>
   <groupId>org.apache.maven.plugins</groupId>
   <artifactId>maven-antrun-plugin</artifactId>
   <version>1.1</version>
   <executions>
      <execution>
         <id>id.pre-clean</id>
         <phase>pre-clean</phase>
         <goals>
            <goal>run</goal>
         </goals>
         <configuration>
            <tasks>
               <echo>pre-clean phase</echo>
            </tasks>
         </configuration>
      </execution>
      <execution>
         <id>id.clean</id>
         <phase>clean</phase>
         <goals>
          <goal>run</goal>
         </goals>
         <configuration>
            <tasks>
               <echo>clean phase</echo>
            </tasks>
         </configuration>
      </execution>
      <execution>
         <id>id.post-clean</id>
         <phase>post-clean</phase>
         <goals>
            <goal>run</goal>
         </goals>
         <configuration>
            <tasks>
               <echo>post-clean phase</echo>
            </tasks>
         </configuration>
      </execution>
   </executions>
   </plugin>
</plugins>
</build>
</project>

Now open command console, go to the folder containing pom.xml and execute the following mvn command.

C:\MVN\project>mvn post-clean

Maven will start processing and display all the phases of clean life cycle

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building project 1.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.pre-clean) @ project ---
[INFO] Executing tasks
     [echo] pre-clean phase
[INFO] Executed tasks
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ project ---
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.clean) @ project ---
[INFO] Executing tasks
     [echo] clean phase
[INFO] Executed tasks
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.post-clean) @ project ---
[INFO] Executing tasks
     [echo] post-clean phase
[INFO] Executed tasks
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.078 s
[INFO] Finished at: 2015-09-26T08:03:06+05:30
[INFO] Final Memory: 7M/247M
[INFO] ------------------------------------------------------------------------

You can try tuning mvn clean command which will display pre-clean and clean, nothing will be executed for post-clean phase.

Default (or Build) Lifecycle

This is the primary life cycle of Maven and is used to build the application. It has following 23 phases.

Lifecycle Phase Description
validate Validates whether project is correct and all necessary information is available to complete the build process.
initialize Initializes build state, for example set properties
generate-sources Generate any source code to be included in compilation phase.
process-sources Process the source code, for example, filter any value.
generate-resources Generate resources to be included in the package.
process-resources Copy and process the resources into the destination directory, ready for packaging phase.
compile Compile the source code of the project.
process-classes Post-process the generated files from compilation, for example to do bytecode enhancement/optimization on Java classes.
generate-test-sources Generate any test source code to be included in compilation phase.
process-test-sources Process the test source code, for example, filter any values.
test-compile Compile the test source code into the test destination directory.
process-test-classes Process the generated files from test code file compilation.
test Run tests using a suitable unit testing framework(Junit is one).
prepare-package Perform any operations necessary to prepare a package before the actual packaging.
package Take the compiled code and package it in its distributable format, such as a JAR, WAR, or EAR file.
pre-integration-test Perform actions required before integration tests are executed. For example, setting up the required environment.
integration-test Process and deploy the package if necessary into an environment where integration tests can be run.
post-integration-test Perform actions required after integration tests have been executed. For example, cleaning up the environment.
verify Run any check-ups to verify the package is valid and meets quality criterias.
install Install the package into the local repository, which can be used as a dependency in other projects locally.
deploy Copies the final package to the remote repository for sharing with other developers and projects.

There are few important concepts related to Maven Lifecycles which are wroth to mention:

  • When a phase is called via Maven command, for example mvn compile, only phases upto and including that phase will execute.

  • Different maven goals will be bound to different phases of Maven lifecycle depending upon the type of packaging (JAR / WAR / EAR).

In the following example, We'll attach maven-antrun-plugin:run goal to few of the phases of Build lifecycle. This will allow us to echo text messages displaying the phases of the lifecycle.

We've updated pom.xml in C:\MVN\project folder.

 
<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.projectgroup</groupId>
<artifactId>project</artifactId>
<version>1.0</version>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<version>1.1</version>
<executions>
   <execution>
      <id>id.validate</id>
      <phase>validate</phase>
      <goals>
         <goal>run</goal>
      </goals>
      <configuration>
         <tasks>
            <echo>validate phase</echo>
         </tasks>
      </configuration>
   </execution>
   <execution>
      <id>id.compile</id>
      <phase>compile</phase>
      <goals>
         <goal>run</goal>
      </goals>
      <configuration>
         <tasks>
            <echo>compile phase</echo>
         </tasks>
      </configuration>
   </execution>
   <execution>
      <id>id.test</id>
      <phase>test</phase>
      <goals>
         <goal>run</goal>
      </goals>
      <configuration>
         <tasks>
            <echo>test phase</echo>
         </tasks>
      </configuration>
   </execution>
   <execution>
         <id>id.package</id>
         <phase>package</phase>
         <goals>
            <goal>run</goal>
         </goals>
         <configuration>
         <tasks>
            <echo>package phase</echo>
         </tasks>
      </configuration>
   </execution>
   <execution>
      <id>id.deploy</id>
      <phase>deploy</phase>
      <goals>
         <goal>run</goal>
      </goals>
      <configuration>
      <tasks>
         <echo>deploy phase</echo>
      </tasks>
      </configuration>
   </execution>
</executions>
</plugin>
</plugins>
</build>
</project>

Now open command console, go the folder containing pom.xml and execute the following mvn command.

C:\MVN\project>mvn compile

Maven will start processing and display phases of build life cycle upto compile phase.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building project 1.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.validate) @ project ---
[INFO] Executing tasks
     [echo] validate phase
[INFO] Executed tasks
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ project --
-
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\project\src\main\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ project ---
[INFO] No sources to compile
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.compile) @ project ---
[INFO] Executing tasks
     [echo] compile phase
[INFO] Executed tasks
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.704 s
[INFO] Finished at: 2015-09-26T08:22:05+05:30
[INFO] Final Memory: 10M/247M
[INFO] ------------------------------------------------------------------------

Site Lifecycle

Maven Site plugin is generally used to create fresh documentation to create reports, deploy site etc.

Phases

  • pre-site

  • site

  • post-site

  • site-deploy

In the following example, We'll attach maven-antrun-plugin:run goal to all the phases of Site lifecycle. This will allow us to echo text messages displaying the phases of the lifecycle.

We've updated pom.xml in C:\MVN\project folder.

<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.projectgroup</groupId>
<artifactId>project</artifactId>
<version>1.0</version>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<version>1.1</version>
   <executions>
      <execution>
         <id>id.pre-site</id>
         <phase>pre-site</phase>
         <goals>
            <goal>run</goal>
         </goals>
         <configuration>
            <tasks>
               <echo>pre-site phase</echo>
            </tasks>
         </configuration>
      </execution>
      <execution>
         <id>id.site</id>
         <phase>site</phase>
         <goals>
         <goal>run</goal>
         </goals>
         <configuration>
            <tasks>
               <echo>site phase</echo>
            </tasks>
         </configuration>
      </execution>
      <execution>
         <id>id.post-site</id>
         <phase>post-site</phase>
         <goals>
            <goal>run</goal>
         </goals>
         <configuration>
            <tasks>
               <echo>post-site phase</echo>
            </tasks>
         </configuration>
      </execution>
      <execution>
         <id>id.site-deploy</id>
         <phase>site-deploy</phase>
         <goals>
            <goal>run</goal>
         </goals>
         <configuration>
            <tasks>
               <echo>site-deploy phase</echo>
            </tasks>
         </configuration>
      </execution>
   </executions>
</plugin>
</plugins>
</build>
</project>

Now open command console, go the folder containing pom.xml and execute the following mvn command.

C:\MVN\project>mvn site

Maven will start processing and display phases of site life cycle upto site phase.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building project 1.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.pre-site) @ project ---
[INFO] Executing tasks
     [echo] pre-site phase
[INFO] Executed tasks
[INFO]
[INFO] --- maven-site-plugin:3.3:site (default-site) @ project ---
[WARNING] Report plugin org.apache.maven.plugins:maven-project-info-reports-plug
in has an empty version.
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten t
he stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support buildin
g such malformed projects.
[INFO] configuring report plugin org.apache.maven.plugins:maven-project-info-rep
orts-plugin:2.8.1
[WARNING] No project URL defined - decoration links will not be relativized!
[INFO] Rendering site with org.apache.maven.skins:maven-default-skin:jar:1.0 ski
n.
[INFO] Generating "Dependency Convergence" report    --- maven-project-info-repo
rts-plugin:2.8.1
[INFO] Generating "Dependency Information" report    --- maven-project-info-repo
rts-plugin:2.8.1
[INFO] Generating "About" report    --- maven-project-info-reports-plugin:2.8.1
[INFO] Generating "Plugin Management" report    --- maven-project-info-reports-p
lugin:2.8.1
[INFO] Generating "Project Plugins" report    --- maven-project-info-reports-plu
gin:2.8.1
[INFO] Generating "Project Summary" report    --- maven-project-info-reports-plu
gin:2.8.1
[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (id.site) @ project ---
[INFO] Executing tasks
     [echo] site phase
[INFO] Executed tasks
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 11.390 s
[INFO] Finished at: 2015-09-26T08:43:45+05:30
[INFO] Final Memory: 18M/247M
[INFO] ------------------------------------------------------------------------

Maven Build Profiles

What is Build Profile?

A Build profile is a set of configuration values which can be used to set or override default values of Maven build. Using a build profile, you can customize build for different environments such as Production v/s Development environments.

Profiles are specified in pom.xml file using its activeProfiles / profiles elements and are triggered in variety of ways. Profiles modify the POM at build time, and are used to give parameters different target environments (for example, the path of the database server in the development, testing, and production environments).

Types of Build Profile

Build profiles are majorly of three types

Type Where it is defined
Per Project Defined in the project POM file, pom.xml
Per User Defined in Maven settings xml file (%USER_HOME%/.m2/settings.xml)
Global Defined in Maven global settings xml file (%M2_HOME%/conf/settings.xml)

Profile Activation

A Maven Build Profile can be activated in various ways.

  • Explicitly using command console input.

  • Through maven settings.

  • Based on environment variables (User/System variables).

  • OS Settings (for example, Windows family).

  • Present/missing files.

Profile Activation Examples

Let us assume following directory structure of your project:

Maven Build Profile

Now, under src/main/resources there are three environment specific files:

File Name Description
env.properties default configuration used if no profile is mentioned.
env.test.properties test configuration when test profile is used.
env.prod.properties production configuration when prod profile is used.

Explicit Profile Activation

In the following example, We'll attach maven-antrun-plugin:run goal to test phase. This will allow us to echo text messages for different profiles. We will be using pom.xml to define different profiles and will activate profile at command console using maven command.

Assume, we've created following pom.xml in C:\MVN\project folder.

<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.projectgroup</groupId>
   <artifactId>project</artifactId>
   <version>1.0</version>
   <profiles>
      <profile>
      <id>test</id>
      <build>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-antrun-plugin</artifactId>
            <version>1.1</version>
            <executions>
               <execution>
                  <phase>test</phase>
                  <goals>
                     <goal>run</goal>
                  </goals>
                  <configuration>
                  <tasks>
                     <echo>Using env.test.properties</echo>
            <copy file="src/main/resources/env.test.properties" tofile
		    ="${project.build.outputDirectory}/env.properties"/>
                  </tasks>
                  </configuration>
               </execution>
            </executions>
         </plugin>
      </plugins>
      </build>
      </profile>
   </profiles>
   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>
   </dependencies>
</project>

And assume, we've created following properties file in C:\MVN\project\src\resources folder.

env.properties

environment=debug

env.test.properties

environment=test

env.prod.properties

environment=prod

Now open command console, go to the folder containing pom.xml and execute the following mvn command. Pass the profile name as argument using -P option.

C:\MVN\project>mvn test -Ptest

Maven will start processing and display the result of test build profile.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building project 1.0
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ project --
-
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] Copying 3 resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ project ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ pr
oject ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\project\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ project
 ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ project ---
[INFO] Surefire report directory: C:\MVN\project\target\surefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.companyname.bank.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.016 sec

Results :

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

[INFO]
[INFO] --- maven-antrun-plugin:1.1:run (default) @ project ---
[INFO] Executing tasks
     [echo] Using env.test.properties
[INFO] Executed tasks
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.953 s
[INFO] Finished at: 2015-09-27T11:54:45+05:30
[INFO] Final Memory: 9M/247M
[INFO] ------------------------------------------------------------------------

Now as an exercise, you can do the following steps

  • Add another profile element to profiles element of pom.xml (copy existing profile element and paste it where profile elements ends).

  • Update id of this profile element from test to normal.

  • Update task section to echo env.properties and copy env.properties to target directory

  • Again repeat above three steps, update id to prod and task section for env.prod.properties

  • That's all. Now you've three build profiles ready (normal / test / prod).

Now open command console, go to the folder containing pom.xml and execute the following mvn commands. Pass the profile names as argument using -P option.

C:\MVN\project>mvn test -Pnormal
C:\MVN\project>mvn test -Pprod

Check the output of build to see the difference.

Profile Activation via Maven Settings

Open Maven settings.xml file available in %USER_HOME%/.m2 directory where %USER_HOME% represents user home directory. If settings.xml file is not there then create a new one.

Add test profile as an active profile using activeProfiles node as shown below in example

<settings 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/settings-1.0.0.xsd">
   <mirrors>
      <mirror>
         <id>maven.dev.snaponglobal.com</id>
         <name>Internal Artifactory Maven repository</name>
         <url>http://repo1.maven.org/maven2/</url>
         <mirrorOf>*</mirrorOf>
      </mirror>
   </mirrors>
   <activeProfiles>
      <activeProfile>test</activeProfile>
   </activeProfiles>
</settings>

Now open command console, go to the folder containing pom.xml and execute the following mvn command. Do not pass the profile name using -P option.Maven will display result of test profile being an active profile.

C:\MVN\project>mvn test

Profile Activation via Environment Variables

Now remove active profile from maven settings.xml and update the test profile mentioned in pom.xml. Add activation element to profile element as shown below.

The test profile will trigger when the system property "env" is specified with the value "test". Create a environment variable "env" and set its value as "test".

<profile>
   <id>test</id>
   <activation>
      <property>
         <name>env</name>
         <value>test</value>
      </property>
   </activation>
</profile>

Let's open command console, go to the folder containing pom.xml and execute the following mvn command.

C:\MVN\project>mvn test

Profile Activation via Operating System

Activation element to include os detail as shown below. This test profile will trigger when the system is windows XP.

<profile>
   <id>test</id>
   <activation>
      <os>
         <name>Windows XP</name>
         <family>Windows</family>
         <arch>x86</arch>
         <version>5.1.2600</version>
      </os>
   </activation>
</profile>

Now open command console, go to the folder containing pom.xml and execute the following mvn commands. Do not pass the profile name using -P option.Maven will display result of test profile being an active profile.

C:\MVN\project>mvn test

Profile Activation via Present/Missing File

Now activation element to include os detail as shown below. The test profile will trigger when target/generated-sources/axistools/wsdl2java/com/companyname/group is missing.

<profile>
   <id>test</id>
   <activation>
      <file>
         <missing>target/generated-sources/axistools/wsdl2java/
		 com/companyname/group</missing>
      </file>
   </activation>
</profile>

Now open command console, go to the folder containing pom.xml and execute the following mvn commands. Do not pass the profile name using -P option.Maven will display result of test profile being an active profile.

C:\MVN\project>mvn test

Maven Repositories

In Maven terminology, a repository is a place i.e. directory where all the project jars, library jar, plugins or any other project specific artifacts are stored and can be used by Maven easily.

Maven repository are of three types

  • local

  • central

  • remote

Local Repository

Maven local repository is a folder location on your machine. It gets created when you run any maven command for the first time.

Maven local repository keeps your project's all dependencies (library jars, plugin jars etc). When you run a Maven build, then Maven automatically downloads all the dependency jars into the local repository.It helps to avoid references to dependencies stored on remote machine every time a project is build.

Maven local repository by default get created by Maven in %USER_HOME% directory. To override the default location, mention another path in Maven settings.xml file available at %M2_HOME%\conf directory.

<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 
   http://maven.apache.org/xsd/settings-1.0.0.xsd">
      <localRepository>C:/MyLocalRepository</localRepository>
</settings>

When you run Maven command, Maven will download dependencies to your custom path.

Central Repository

Maven central repository is repository provided by Maven community. It contains a large number of commonly used libraries.

When Maven does not find any dependency in local repository, it starts searching in central repository using following URL: http://repo1.maven.org/maven2/

Key concepts of Central repository

  • This repository is managed by Maven community.

  • It is not required to be configured.

  • It requires internet access to be searched.

To browse the content of central maven repository, maven community has provided a URL: http://search.maven.org/#browse. Using this library, a developer can search all the available libraries in central repository.

Remote Repository

Sometime, Maven does not find a mentioned dependency in central repository as well then it stopped build process and output error message to console. To prevent such situation, Maven provides concept of Remote Repository which is developer's own custom repository containing required libraries or other project jars.

For example, using below mentioned POM.xml,Maven will download dependency (not available in central repository) from Remote Repositories mentioned in the same pom.xml.

<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.projectgroup</groupId>
   <artifactId>project</artifactId>
   <version>1.0</version>
   <dependencies>
      <dependency>
         <groupId>com.companyname.common-lib</groupId>
         <artifactId>common-lib</artifactId>
         <version>1.0.0</version>
      </dependency>
   <dependencies>
   <repositories>
      <repository>
         <id>companyname.lib1</id>
         <url>http://download.companyname.org/maven2/lib1</url>
      </repository>
      <repository>
         <id>companyname.lib2</id>
         <url>http://download.companyname.org/maven2/lib2</url>
      </repository>
   </repositories>
</project>

Maven Dependency Search Sequence

When we execute Maven build commands, Maven starts looking for dependency libraries in the following sequence:

  • Step 1 - Search dependency in local repository, if not found, move to step 2 else if found then do the further processing.

  • Step 2 - Search dependency in central repository, if not found and remote repository/repositories is/are mentioned then move to step 4 else if found, then it is downloaded to local repository for future reference.

  • Step 3 - If a remote repository has not been mentioned, Maven simply stops the processing and throws error (Unable to find dependency).

  • Step 4 - Search dependency in remote repository or repositories, if found then it is downloaded to local repository for future reference otherwise Maven as expected stop processing and throws error (Unable to find dependency).

Maven Plugins

What are Maven Plugins?

Maven is actually a plugin execution framework where every task is actually done by plugins. Maven Plugins are generally used to :

  • create jar file

  • create war file

  • compile code files

  • unit testing of code

  • create project documentation

  • create project reports

A plugin generally provides a set of goals and which can be executed using following syntax:

mvn [plugin-name]:[goal-name]

For example, a Java project can be compiled with the maven-compiler-plugin's compile-goal by running following command

mvn compiler:compile

Plugin Types

Maven provided following two types of Plugins:

Type Description
Build plugins They execute during the build and should be configured in the <build/> element of pom.xml
Reporting plugins They execute during the site generation and they should be configured in the <reporting/> element of the pom.xml

Following is the list of few common plugins:

Plugin Description
clean Clean up target after the build. Deletes the target directory.
compiler Compiles Java source files.
surefile Run the JUnit unit tests. Creates test reports.
jar Builds a JAR file from the current project.
war Builds a WAR file from the current project.
javadoc Generates Javadoc for the project.
antrun Runs a set of ant tasks from any phase mentioned of the build.

Example

We've used maven-antrun-plugin extensively in our examples to print data on console. See Maven Build Profiles chapter. Let to understand it in a better way let's create a pom.xml in C:\MVN\project folder.

<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.projectgroup</groupId>
<artifactId>project</artifactId>
<version>1.0</version>
<build>
<plugins>
   <plugin>
   <groupId>org.apache.maven.plugins</groupId>
   <artifactId>maven-antrun-plugin</artifactId>
   <version>1.1</version>
   <executions>
      <execution>
         <id>id.clean</id>
         <phase>clean</phase>
         <goals>
            <goal>run</goal>
         </goals>
         <configuration>
            <tasks>
               <echo>clean phase</echo>
            </tasks>
         </configuration>
      </execution>     
   </executions>
   </plugin>
</plugins>
</build>
</project>

Next, open command console and go to the folder containing pom.xml and execute the following mvn command.

C:\MVN\project>mvn clean

Maven will start processing and display clean phase of clean life cycle

[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------
[INFO] Building Unnamed - com.companyname.projectgroup:project:jar:1.0
[INFO]    task-segment: [post-clean]
[INFO] ------------------------------------------------------------------
[INFO] [clean:clean {execution: default-clean}]
[INFO] [antrun:run {execution: id.clean}]
[INFO] Executing tasks
     [echo] clean phase
[INFO] Executed tasks
[INFO] ------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------
[INFO] Total time: < 1 second
[INFO] Finished at: Sat Jul 07 13:38:59 IST 2012
[INFO] Final Memory: 4M/44M
[INFO] ------------------------------------------------------------------

The above example illustrates the following key concepts:

  • Plugins are specified in pom.xml using plugins element.

  • Each plugin can have multiple goals.

  • You can define phase from where plugin should starts its processing using its phase element. We've used clean phase.

  • You can configure tasks to be executed by binding them to goals of plugin. We've bound echo task with run goal of maven-antrun-plugin.

  • That's it, Maven will handle the rest. It will download the plugin if not available in local repository and starts its processing.

Creating Java Project using Maven

Maven uses archetype plugins to create projects. To create a simple java application, we'll use maven-archetype-quickstart plugin. In example below, We'll create a maven based java application project in C:\MVN folder.

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

C:\MVN>mvn archetype:generate
-DgroupId=com.companyname.bank 
-DartifactId=consumerBanking 
-DarchetypeArtifactId=maven-archetype-quickstart 
-DinteractiveMode=false

Maven will start processing and will create the complete java application project structure.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-archetype-plugin:2.4:generate (default-cli) > generate-sources
@ standalone-pom >>>
[INFO]
[INFO] <<< maven-archetype-plugin:2.4:generate (default-cli) < generate-sources
@ standalone-pom <<<
[INFO]
[INFO] --- maven-archetype-plugin:2.4:generate (default-cli) @ standalone-pom --
-
[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.companyname.bank
[INFO] Parameter: packageName, Value: com.companyname.bank
[INFO] Parameter: package, Value: com.companyname.bank
[INFO] Parameter: artifactId, Value: consumerBanking
[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 SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 03:19 min
[INFO] Finished at: 2015-09-26T12:18:26+05:30
[INFO] Final Memory: 15M/247M
[INFO] ------------------------------------------------------------------------

Now go to C:/MVN directory. You'll see a java application project created named consumerBanking (as specified in artifactId). Maven uses a standard directory layout as shown below:

Java application project structure

Using above example, we can understand following key concepts

Folder Structure Description
consumerBanking contains src folder and pom.xml
src/main/java contains java code files under the package structure (com/companyName/bank).
src/main/test contains test java code files under the package structure (com/companyName/bank).
src/main/resources it contains images/properties files (In above example, we need to create this structure manually).

If you see, Maven also created a sample Java Source file and Java Test file. Open C:\MVN\consumerBanking\src\main\java\com\companyname\bank folder, you will see App.java.

package com.companyname.bank;

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

Open C:\MVN\consumerBanking\src\test\java\com\companyname\bank folder, you will see AppTest.java.

package com.companyname.bank;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

/**
 * Unit test for simple App.
 */
public class AppTest extends TestCase 
{
    /**
     * Create the test case
     *
     * @param testName name of the test case
     */
    public AppTest( String testName )
    {
        super( testName );
    }

    /**
     * @return the suite of tests being tested
     */
    public static Test suite()
    {
        return new TestSuite( AppTest.class );
    }

    /**
     * Rigourous Test :-)
     */
    public void testApp()
    {
        assertTrue( true );
    }
}

Developers are required to place their files as mentioned in table above and Maven handles the all the build related complexities.

In next section, we'll discuss how to build and test the project using maven Maven Build & Test Project.

Build & Test Java Project using Maven

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 consumerBanking 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.companyname.projectgroup</groupId>
      <artifactId>project</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 file App.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 mvn command.

C:\MVN\consumerBanking>mvn clean package

Maven will start building the project.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building consumerBanking 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ consumerBanking ---
[INFO] Deleting C:\MVN\consumerBanking\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ consumerBanking ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\consumerBanking\src\main\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ consumerBanking ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. build is platform dependent!
[INFO] Compiling 1 source file to C:\MVN\consumerBanking\target\classes
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ consumerBanking ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\consumerBanking\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ consumerBanking ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. b
uild is platform dependent!
[INFO] Compiling 1 source file to C:\MVN\consumerBanking\target\test-classes
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ consumerBanking ---
[INFO] Surefire report directory: C:\MVN\consumerBanking\target\surefire-reports


-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.companyname.bank.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.063 sec

Results :

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

[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ consumerBanking ---
[INFO] Building jar: C:\MVN\consumerBanking\target\consumerBanking-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 14.406 s
[INFO] Finished at: 2015-09-27T17:58:06+05:30
[INFO] Final Memory: 14M/247M
[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 consumerBanking\target folder as consumerBanking-1.0-SNAPSHOT.jar.

  • Test reports are available in consumerBanking\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\consumerBanking\target\classes directory and execute the following java command.

C:\MVN\consumerBanking\target\classes>java com.companyname.bank.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\consumerBanking\src\main\java\com\companyname\bank folder, create Util class in it as Util.java.

package com.companyname.bank;

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

Update App class to use Util class.

package com.companyname.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 mvn command.

C:\MVN\consumerBanking>mvn clean compile

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

C:\MVN\consumerBanking\target\classes>java -cp com.companyname.bank.App

You will see the result

Hello World!

Maven - External Dependencies

Now as you know Maven does the dependency management using concept of Maven Repositories. But what happens if dependency is not available in any of remote repositories and central repository? Maven provides answer for such scenario using concept of External Dependency.

For an example, let us do the following changes to project created in Maven Creating Project section.

  • Add lib folder to src folder

  • Copy any jar into the lib folder. We've used ldapjdk.jar, which is a helper library for LDAP operations.

Now our project structure should look like following:

external repository project structure

Here you are having your own library specific to project, which is very usual case and it can contain jars which may not be available in any repository for maven to download from. If your code is using this library with Maven then Maven build will fail because it cannot download or refer to this library during compilation phase.

To handle the situation, let's add this external dependency to maven pom.xml using following way.

<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/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.companyname.bank</groupId>
   <artifactId>consumerBanking</artifactId>
   <packaging>jar</packaging>
   <version>1.0-SNAPSHOT</version>
   <name>consumerBanking</name>
   <url>http://maven.apache.org</url>

   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>

      <dependency>
         <groupId>ldapjdk</groupId>
         <artifactId>ldapjdk</artifactId>
         <scope>system</scope>
         <version>1.0</version>
         <systemPath>${basedir}\src\lib\ldapjdk.jar</systemPath>
      </dependency>
   </dependencies>

</project>

Look at the second dependency element under dependencies in above example which clears following key concepts about External Dependency.

  • External dependencies (library jar location) can be configured in pom.xml in same way as other dependencies.

  • Specify groupId same as name of the library.

  • Specify artifactId same as name of the library.

  • Specify scope as system.

  • Specify system path relative to project location.

Hope now you are clear about external dependencies and you will be able to specify external dependencies in your Maven project.

Maven - Project Documents

This tutorial will teach you how to create documentation of the application in one go. So let's start, go to C:/MVN directory where you had created your java consumerBanking application. Open consumerBanking folder and execute the following mvn command.

C:\MVN>mvn site

Maven will start building the project.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building consumerBanking 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-site-plugin:3.3:site (default-site) @ consumerBanking ---
[WARNING] Report plugin org.apache.maven.plugins:maven-project-info-reports-plugin has an empty version.
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[INFO] configuring report plugin org.apache.maven.plugins:maven-project-info-reports-plugin:2.8.1
[INFO] Relativizing decoration links with respect to project URL: http://maven.apache.org
[INFO] Rendering site with org.apache.maven.skins:maven-default-skin:jar:1.0 skin.
[INFO] Generating "Dependencies" report    --- maven-project-info-reports-plugin:2.8.1
[INFO] Generating "Dependency Convergence" report    --- maven-project-info-reports-plugin:2.8.1
[INFO] Generating "Dependency Information" report    --- maven-project-info-reports-plugin:2.8.1
[INFO] Generating "About" report    --- maven-project-info-reports-plugin:2.8.1
[INFO] Generating "Plugin Management" report    --- maven-project-info-reports-plugin:2.8.1
[INFO] Generating "Project Plugins" report    --- maven-project-info-reports-plugin:2.8.1
[INFO] Generating "Project Summary" report    --- maven-project-info-reports-plugin:2.8.1
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 37.828 s
[INFO] Finished at: 2015-09-27T12:11:27+05:30
[INFO] Final Memory: 23M/247M
[INFO] ------------------------------------------------------------------------

That's it. Your project documentation is ready. Maven has created a site within target directory.

documentation site pages

Open C:\MVN\consumerBanking\target\site folder. Click on index.html to see the documentation.

consumer web  page

Maven creates the documentation using a documentation-processing engine called Doxia which reads multiple source formats into a common document model.To write documentation for your project, you can write your content in a following few commonly used formats which are parsed by Doxia.

Format NameDescriptionReference
APTA Plain Text document format

doxia format

XDocA Maven 1.x documentation format

jakarta format

FMLUsed for FAQ documents

fml format

XHTMLExtensible HTML

XHTML wiki

Maven - Project Templates

Maven provides users,a very large list of different types of project templates (614 in numbers) using concept of Archetype. Maven helps users to quickly start a new java project using following command

mvn archetype:generate

What is Archetype?

Archetype is a Maven plugin whose task is to create a project structure as per its template. We are going to use quickstart archetype plugin to create a simple java application here.

Using Project Template

Let's open command console, go the C:\ > MVN directory and execute the following mvn command

C:\MVN>mvn archetype:generate 

Maven will start processing and will ask to choose required archetype

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-archetype-plugin:2.4:generate (default-cli) > generate-sources@ standalone-pom >>>
[INFO]
[INFO] <<< maven-archetype-plugin:2.4:generate (default-cli) < generate-sources@ standalone-pom <<<
[INFO]
[INFO] --- maven-archetype-plugin:2.4:generate (default-cli) @ standalone-pom ---
[INFO] Generating project in Interactive mode
[WARNING] No archetype found in remote catalog. Defaulting to internal catalog
[INFO] No archetype defined. Using maven-archetype-quickstart (org.apache.maven.
archetypes:maven-archetype-quickstart:1.0)
Choose archetype:
1: internal -> org.apache.maven.archetypes:maven-archetype-archetype (An archetype which contains a sample archetype.)
2: internal -> org.apache.maven.archetypes:maven-archetype-j2ee-simple (An archetype which contains a simplifed sample J2EE application.)
3: internal -> org.apache.maven.archetypes:maven-archetype-plugin (An archetypewhich contains a sample Maven plugin.)
4: internal -> org.apache.maven.archetypes:maven-archetype-plugin-site (An archetype which contains a sample Maven plugin site.
      This archetype can be layered upon an existing Maven plugin project.)
5: internal -> org.apache.maven.archetypes:maven-archetype-portlet (An archetype which contains a sample JSR-268 Portlet.)
6: internal -> org.apache.maven.archetypes:maven-archetype-profiles ()
7: internal -> org.apache.maven.archetypes:maven-archetype-quickstart (An archetype which contains a sample Maven project.)
8: internal -> org.apache.maven.archetypes:maven-archetype-site (An archetype which contains a sample Maven site which demonstrates
      some of the supported document types like APT, XDoc, and FML and demonstrates how
      to i18n your site. This archetype can be layered upon an existing Maven project.)
9: internal -> org.apache.maven.archetypes:maven-archetype-site-simple (An archetype which contains a sample Maven site.)
10: internal -> org.apache.maven.archetypes:maven-archetype-webapp (An archetype
 which contains a sample Maven Webapp project.)
Choose a number or apply filter (format: [groupId:]artifactId, case sensitive contains): 7:

Press Enter to choose to default option(7: maven-archetype-quickstart). Maven will ask for project detail. Enter project detail as asked.Press Enter if default value is provided. You can override them by entering your own value.

Define value for property 'groupId': : com.companyname.insurance
Define value for property 'artifactId': : health
Define value for property 'version': 1.0-SNAPSHOT:
Define value for property 'package': com.companyname.insurance:

Maven will ask for project detail confirmation. Press enter or press Y

Confirm properties configuration:
groupId: com.companyname.insurance
artifactId: health
version: 1.0-SNAPSHOT
package: com.companyname.insurance
Y:

Now Maven will start creating project structure and will display the following:

[INFO] -------------------------------------------------------------------------
---
[INFO] Using following parameters for creating project from Old (1.x) Archetype:
 maven-archetype-quickstart:1.1
[INFO] -------------------------------------------------------------------------
---
[INFO] Parameter: groupId, Value: com.companyname.insurance
[INFO] Parameter: packageName, Value: com.companyname.insurance
[INFO] Parameter: package, Value: com.companyname.insurance
[INFO] Parameter: artifactId, Value: health
[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\health
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 02:29 min
[INFO] Finished at: 2015-09-27T12:18:02+05:30
[INFO] Final Memory: 16M/247M
[INFO] ------------------------------------------------------------------------

Created Project

Now go to C:\ > MVN directory. You'll see a java application project created named health which was given as artifactId at the time of project creation. Maven will create a standard directory layout for the project as shown below:

project structure

Created POM.xml

Maven generates a POM.xml file for the project as listed below:

<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.insurance</groupId>
   <artifactId>health</artifactId>
   <version>1.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>health</name>
   <url>http://maven.apache.org</url>
   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
   <dependencies>
      <dependency>
      <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>
   </dependencies>
</project>

Created App.java

Maven generates sample java source file, App.java for the project as listed below:

Location: C:\ > MVN > health > src > main > java > com > companyname > insurance > App.java

package com.companyname.insurance;

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

Created AppTest.java

Maven generates sample java source test file, AppTest.java for the project as listed below:

Location: C:\ > MVN > health > src > test > java > com > companyname > insurance > AppTest.java

package com.companyname.insurance;

import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;

/**
 * Unit test for simple App.
 */
public class AppTest 
    extends TestCase
{
    /**
     * Create the test case
     *
     * @param testName name of the test case
     */
    public AppTest( String testName )
    {
        super( testName );
    }

    /**
     * @return the suite of tests being tested
     */
    public static Test suite()
    {
        return new TestSuite( AppTest.class );
    }

    /**
     * Rigourous Test :-)
     */
    public void testApp()
    {
        assertTrue( true );
    }
}

That's it. Now you can see the power of Maven. You can create any kind of project using single command in maven and can kick-start your development.

Maven - Snapshots

A large software application generally consists of multiple modules and it is common scenario where multiple teams are working on different modules of same application. For example consider a team is working on the front end of the application as app-ui project (app-ui.jar:1.0) and they are using data-service project (data-service.jar:1.0).

Now it may happen that team working on data-service is undergoing bug fixing or enhancements at rapid pace and they are releasing the library to remote repository almost every other day.

Now if data-service team uploads a new version every other day then following problem will arise

  • data-service team should tell app-ui team every time when they have released an updated code.

  • app-ui team required to update their pom.xml regularly to get the updated version

To handle such kind of situation, SNAPSHOT concept comes into play.

What is SNAPSHOT?

SNAPSHOT is a special version that indicates a current development copy. Unlike regular versions, Maven checks for a new SNAPSHOT version in a remote repository for every build.

Now data-service team will release SNAPSHOT of its updated code everytime to repository say data-service:1.0-SNAPSHOT replacing a older SNAPSHOT jar.

Snapshot vs Version

In case of Version, if Maven once downloaded the mentioned version say data-service:1.0, it will never try to download a newer 1.0 available in repository. To download the updated code, data-service version is be upgraded to 1.1.

In case of SNAPSHOT, Maven will automatically fetch the latest SNAPSHOT (data-service:1.0-SNAPSHOT) everytime app-ui team build their project.

app-ui pom.xml

app-ui project is using 1.0-SNAPSHOT of data-service

<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>app-ui</groupId>
   <artifactId>app-ui</artifactId>
   <version>1.0</version>
   <packaging>jar</packaging>
   <name>health</name>
   <url>http://maven.apache.org</url>
   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
   <dependencies>
      <dependency>
      <groupId>data-service</groupId>
         <artifactId>data-service</artifactId>
         <version>1.0-SNAPSHOT</version>
         <scope>test</scope>
      </dependency>
   </dependencies>
</project>

data-service pom.xml

data-service project is releasing 1.0-SNAPSHOT for every minor change

<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>data-service</groupId>
   <artifactId>data-service</artifactId>
   <version>1.0-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>health</name>
   <url>http://maven.apache.org</url>
   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
   </project>

Although, In case of SNAPSHOT, Maven automatically fetches the latest SNAPSHOT on daily basis. You can force maven to download latest snapshot build using -U switch to any maven command.

mvn clean package -U

Let's open command console, go the C:\ > MVN > app-ui directory and execute the following mvn command.

C:\MVN\app-ui>mvn clean package -U

Maven will start building the project after downloading latest SNAPSHOT of data-service.

[INFO] Scanning for projects...
[INFO] -------------------------------------------------------------------
[INFO] Building consumerBanking
[INFO]    task-segment: [clean, package]
[INFO] -------------------------------------------------------------------
[INFO] Downloading data-service:1.0-SNAPSHOT
[INFO] 290K downloaded.
[INFO] [clean:clean {execution: default-clean}]
[INFO] Deleting directory C:\MVN\app-ui\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\app-ui\src\main\
resources
[INFO] [compiler:compile {execution: default-compile}]
[INFO] Compiling 1 source file to C:\MVN\app-ui\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\app-ui\src\test\
resources
[INFO] [compiler:testCompile {execution: default-testCompile}]
[INFO] Compiling 1 source file to C:\MVN\app-ui\target\test-classes
[INFO] [surefire:test {execution: default-test}]
[INFO] Surefire report directory: C:\MVN\app-ui\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\app-ui\target\
app-ui-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2 seconds
[INFO] Finished at: 2015-09-27T12:30:02+05:30
[INFO] Final Memory: 16M/89M
[INFO] ------------------------------------------------------------------------

Maven - Build Automation

Build Automation defines the scenario where dependent project(s) build process gets started once the project build is successfully completed,in order to ensure that dependent project(s) is/are stable.

Example

Consider a team is developing a project bus_core_api on which two other projects app_web_ui and app_desktop_ui are dependent. bus_core_api project is present in C:\ > MVN directory and app_web_ui and app_desktop_ui are present in C:\ > MVN > projects directory

app_web_ui project is using 1.0-SNAPSHOT of bus_core_api project

<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>app_web_ui</groupId>
   <artifactId>app_web_ui</artifactId>
   <version>1.0</version>
   <packaging>jar</packaging>
   <name>app_web_ui</name>
   <url>http://maven.apache.org</url>
   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>
	  <dependency>
         <groupId>bus_core_api</groupId>
         <artifactId>bus_core_api</artifactId>
         <version>1.0-SNAPSHOT</version>
		 <scope>system</scope>
		 <systemPath>C:\MVN\bus_core_api\target\bus_core_api-1.0-SNAPSHOT.jar</systemPath>
      </dependency>
   </dependencies>
</project>

app_desktop_ui project is using 1.0-SNAPSHOT of bus_core_api project

<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>app_desktop_ui</groupId>
   <artifactId>app_desktop_ui</artifactId>
   <version>1.0</version>
   <packaging>jar</packaging>
   <name>app_desktop_ui</name>
   <url>http://maven.apache.org</url>
   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   </properties>
   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>
	  <dependency>
         <groupId>bus_core_api</groupId>
         <artifactId>bus_core_api</artifactId>
         <version>1.0-SNAPSHOT</version>
		 <scope>system</scope>
		 <systemPath>C:\MVN\bus_core_api\target\bus_core_api-1.0-SNAPSHOT.jar</systemPath>
      </dependency>
   </dependencies>
</project>

bus_core_api project

<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>bus_core_api</groupId>
   <artifactId>bus_core_api</artifactId>
   <version>1.0-SNAPSHOT</version>
   <packaging>jar</packaging>   
</project>

Now teams of app_web_ui and app_desktop_ui projects require that their build process should kick off whenever bus_core_api project changes.

Using snapshot ensures that the latest bus_core_api project should be used but to meet above requirement we need to do something extra.

We've two ways

  • Add a post-build goal in bus_core_api pom to kick-off app_web_ui and app_desktop_ui builds.

  • Use a Continuous Integration (CI) Server like Hudson to manage build automation automatically.

Using Maven

Update bus_core_api project pom.xml

<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>bus_core_api</groupId>
   <artifactId>bus_core_api</artifactId>
   <packaging>jar</packaging>
   <version>1.0-SNAPSHOT</version>
   <build>
      <plugins>
         <plugin>            
            <artifactId>maven-invoker-plugin</artifactId>
            <version>2.0.0</version>
            <configuration>
               <debug>true</debug>		
			   <cloneProjectsTo>${project.build.directory}/it</cloneProjectsTo>			   
	           <projectsDirectory>C:/MVN/projects</projectsDirectory>			   
            </configuration>			
            <executions>
               <execution>
                  <id>integration-test</id>
                  <goals>
                     <goal>run</goal>
                  </goals>
               </execution>
            </executions>
         </plugin>
      </plugins>
   </build>
   <dependencies>
      <dependency>
         <groupId>junit</groupId>
         <artifactId>junit</artifactId>
         <version>3.8.1</version>
         <scope>test</scope>
      </dependency>     
   </dependencies>
</project>

Let's open command console, go the C:\ > MVN > bus_core_api directory and execute the following mvn command.

C:\MVN\bus_core_api>mvn verify

Maven will start building the project bus_core_api.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building bus_core_api 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ bus_core_api ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\bus_core_api\src\main\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ bus_core_api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ bus_core_api ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\bus_core_api\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ bus_core_api ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ bus_core_api ---
[INFO] Surefire report directory: C:\MVN\bus_core_api\target\surefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running bus_core_api.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.047 sec

Results :

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

[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ bus_core_api ---
[INFO]
[INFO] --- maven-invoker-plugin:2.0.0:run (integration-test) @ bus_core_api ---
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. build is platform dependent!
[INFO] Building: app_desktop_ui\pom.xml
[INFO] ..SUCCESS (10.7 s)
[INFO] Building: app_web_ui\pom.xml
[INFO] ..SUCCESS (11.5 s)
[INFO] Building: bus_core_api\pom.xml
[INFO] ..SUCCESS (12.8 s)
[INFO] -------------------------------------------------
[INFO] Build Summary:
[INFO]   Passed: 3, Failed: 0, Errors: 0, Skipped: 0
[INFO] -------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 42.421 s
[INFO] Finished at: 2015-09-27T17:41:42+05:30
[INFO] Final Memory: 12M/247M
[INFO] ------------------------------------------------------------------------

Using Continuous Integration Service with Maven

Using a CI Server is more preferable as developers are not required to updated bus_core_api project pom everytime a new project, for example app-mobile-ui is added as dependent project on bus_core_api project. Hudson automatically manages build automation using Maven dependency management.

automated build

Hudson considers each project build as job. Once a project code is checked-in to SVN (or any Source Management Tool mapped to Hudson), Hudson starts its build job and once this job get completed, it start other dependent jobs(other dependent projects) automatically.

In above example, when bus-core-ui source code is updated in SVN, Hudson starts its build. Once build is successful. Hudson looks for dependent projects automatically, and starts building app_web_ui and app_desktop_ui projects.

Maven - Deployment Automation

In project development, normally a deployment process consists of following steps

  • Check-in the code from all project in progress into the SVN or source code repository and tag it.

  • Download the complete source code from SVN.

  • Build the application.

  • Store the build output either WAR or EAR file to a common network location.

  • Get the file from network and deploy the file to the production site.

  • Updated the documentation with date and updated version number of the application.

Problem Statement

There are normally multiple people involved in above mentioned deployment process. One team may handles check-in of code, other may handle build and so on. It is very likely that any step may get missed out due to manual efforts involved and owing to multi-team environment. For example, older build may not be replaced on network machine and deployment team deployed the older build again.

Solution

Automate the deployment process by combining
  • Maven, to build and release projects,

  • SubVersion, source code repository, to manage source code,

  • and Remote Repository Manager (Jfrog/Nexus) to manage project binaries.

Update Project POM.xml

We'll be using Maven Release plug-in to create an automated release process.

For Example: bus-core-api project POM.xml

<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>bus-core-api</groupId>
   <artifactId>bus-core-api</artifactId>
   <version>1.0-SNAPSHOT</version>
   <packaging>jar</packaging> 
   <scm>
      <url>http://www.svn.com</url>
      <connection>scm:svn:http://localhost:8080/svn/jrepo/trunk/
      Framework</connection>
      <developerConnection>scm:svn:${username}/${password}@localhost:8080:
      common_core_api:1101:code</developerConnection>
   </scm>
   <distributionManagement>
      <repository>
         <id>Core-API-Java-Release</id>
         <name>Release repository</name>
         <url>http://localhost:8081/nexus/content/repositories/
         Core-Api-Release</url>
      </repository>
   </distributionManagement>
   <build>
      <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-release-plugin</artifactId>
            <version>2.0-beta-9</version>
            <configuration>
               <useReleaseProfile>false</useReleaseProfile>
               <goals>deploy</goals>
               <scmCommentPrefix>[bus-core-api-release-checkin]-<
               /scmCommentPrefix>
            </configuration>
         </plugin>
      </plugins>
   </build>
</project>

In Pom.xml, following are the important elements we've used

Element Description
SCM Configures the SVN location from where Maven will check out the source code.
Repositories Location where built WAR/EAR/JAR or any other artifact will be stored after code build is successful.
Plugin maven-release-plugin is configured to automate the deployment process.

Maven Release Plug-in

The Maven does following useful tasks using maven-release-plugin.

mvn release:clean

It cleans the workspace in case the last release process was not successful.

mvn release:rollback

Rollback the changes done to workspace code and configuration in case the last release process was not successful.

mvn release:prepare

Performs multiple number of operations

  • Checks whether there are any uncommitted local changes or not

  • Ensures that there are no SNAPSHOT dependencies

  • Changes the version of the application and removes SNAPSHOT from the version to make release

  • Update pom files to SVN.

  • Run test cases

  • Commit the modified POM files

  • Tag the code in subversion

  • Increment the version number and append SNAPSHOT for future release

  • Commit the modified POM files to SVN.

mvn release:perform

Checks out the code using the previously defined tag and run the Maven deploy goal to deploy the war or built artifact to repository.

Let's open command console, go the C:\ > MVN >bus-core-api directory and execute the following mvn command.

C:\MVN\bus-core-api>mvn release:prepare

Maven will start building the project. Once build is successful run the following mvn command.

C:\MVN\bus-core-api>mvn release:perform

Once build is successful you can verify the uploaded JAR file in your repository.

Maven - Web Application

This tutorial will teach you how to manage a web based project using version control system Maven. Here you will learn how to create/build/deploy and run a web application:

Create Web Application

To create a simple java web application, we'll use maven-archetype-webapp plugin. So let's open command console, go the C:\MVN directory and execute the following mvn command.

C:\MVN>mvn archetype:generate 
-DgroupId=com.companyname.automobile 
-DartifactId=trucks
-DarchetypeArtifactId=maven-archetype-webapp 
-DinteractiveMode=false

Maven will start processing and will create the complete web based java application project structure.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] >>> maven-archetype-plugin:2.4:generate (default-cli) > generate-sources
@ standalone-pom >>>
[INFO]
[INFO] <<< maven-archetype-plugin:2.4:generate (default-cli) < generate-sources
@ standalone-pom <<<
[INFO]
[INFO] --- maven-archetype-plugin:2.4:generate (default-cli) @ standalone-pom --
-
[INFO] Generating project in Batch mode
[WARNING] No archetype found in remote catalog. Defaulting to internal catalog
[INFO] -------------------------------------------------------------------------
---
[INFO] Using following parameters for creating project from Old (1.x) Archetype:
 maven-archetype-webapp:1.0
[INFO] -------------------------------------------------------------------------
---
[INFO] Parameter: groupId, Value: com.companyname.automobile
[INFO] Parameter: packageName, Value: com.companyname.automobile
[INFO] Parameter: package, Value: com.companyname.automobile
[INFO] Parameter: artifactId, Value: trucks
[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\trucks
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 19.016 s
[INFO] Finished at: 2015-09-27T17:47:56+05:30
[INFO] Final Memory: 16M/247M
[INFO] ------------------------------------------------------------------------

Now go to C:/MVN directory. You'll see a java application project created named trucks (as specified in artifactId).

Java web application project structure

Maven uses a standard directory layout. Using above example, we can understand following key concepts

Folder Structure Description
trucks contains src folder and pom.xml
src/main/webapp contains index.jsp and WEB-INF folder.
src/main/webapp/WEB-INF contains web.xml
src/main/resources it contains images/properties files .

POM.xml

<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/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.companyname.automobile</groupId>
   <artifactId>trucks</artifactId>
   <packaging>war</packaging>
   <version>1.0-SNAPSHOT</version>
   <name>trucks Maven Webapp</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>
   <build>
      <finalName>trucks</finalName>
   </build>
</project>

If you see, Maven also created a sample JSP Source file

Open C:\ > MVN > trucks > src > main > webapp > folder, you will see index.jsp.

<html>
   <body>
      <h2>Hello World!</h2>
   </body>
</html>

Build Web Application

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

C:\MVN\trucks>mvn clean package

Maven will start building the project.

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building trucks Maven Webapp 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ trucks ---
[INFO] Deleting C:\MVN\trucks\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ trucks ---

[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ trucks ---
[INFO] No sources to compile
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ tr
ucks ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\trucks\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ trucks
---
[INFO] No sources to compile
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ trucks ---
[INFO] No tests to run.
[INFO]
[INFO] --- maven-war-plugin:2.2:war (default-war) @ trucks ---
[INFO] Packaging webapp
[INFO] Assembling webapp [trucks] in [C:\MVN\trucks\target\trucks]
[INFO] Processing war project
[INFO] Copying webapp resources [C:\MVN\trucks\src\main\webapp]
[INFO] Webapp assembled in [93 msecs]
[INFO] Building war: C:\MVN\trucks\target\trucks.war
[INFO] WEB-INF\web.xml already added, skipping
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.766 s
[INFO] Finished at: 2015-09-27T17:53:05+05:30
[INFO] Final Memory: 11M/247M
[INFO] ------------------------------------------------------------------------

Deploy Web Application

Now copy the trucks.war created in C:\ > MVN > trucks > target > folder to your webserver webapp directory and restart the webserver.

Test Web Application

Run the web-application using URL : http://<server-name>:<port-number>/trucks/index.jsp

Verify the output.

web page

Maven - Eclispe IDE

Eclipse provides an excellent plugin m2eclipse which seamlessly integrates Maven and Eclipse together.

Some of features of m2eclipse are listed below

  • You can run Maven goals from Eclipse.

  • You can view the output of Maven commands inside the Eclipse using its own console.

  • You can update maven dependencies with IDE.

  • You can Launch Maven builds from within Eclipse.

  • It does the dependency management for Eclipse build path based on Maven's pom.xml.

  • It resolves Maven dependencies from the Eclipse workspace without installing to local Maven repository (requires dependency project be in same workspace).

  • It automatic downloads required dependencies and sources from the remote Maven repositories.

  • It provides wizards for creating new Maven projects, pom.xml and to enable Maven support on existing projects

  • It provides quick search for dependencies in remote Maven repositories

Installing m2eclipse plugin

Use one of the following links to install m2eclipse:

EclipseURL
Eclipse 3.5 (Gallileo)

Installing m2eclipse in Eclipse 3.5 (Gallileo)

Eclipse 3.6 (Helios)

Installing m2eclipse in Eclipse 3.6 (Helios)

Following example will help you to leverage benefits of integrating Eclipse and maven.

Import a maven project in Eclipse

  • Open Eclipse.

  • Select File > Import > option.

  • Select Maven Projects Option. Click on Next Button.

Import a maven project in Eclipse.
  • Select Project location, where a project was created using Maven. We've create a Java Project consumerBanking.See Maven Creating Project to see how to create a project using Maven.

  • Click Finish Button.

Import a maven project in Eclipse.

Now, you can see the maven project in eclipse.

maven project in Eclipse.

Now, have a look at consumerBanking project properties.You can see that Eclipse has added Maven dependencies to java build path.

Java Build Path having Maven dependencies.

Now, Its time to build this project using maven capability of eclipse.

  • Right Click on consumerBanking project to open context menu.

  • Select Run as option

  • Then maven package option

Maven will start building the project. You can see the output in Eclipse Console

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building consumerBanking 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ consumerBanking ---
[INFO] Deleting C:\MVN\consumerBanking\target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ consumerBanking ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\consumerBanking\src\main\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ consumerBanking ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. build is platform dependent!
[INFO] Compiling 1 source file to C:\MVN\consumerBanking\target\classes
[INFO]
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ consumerBanking ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources,
i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory C:\MVN\consumerBanking\src\test\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ consumerBanking ---
[INFO] Changes detected - recompiling the module!
[WARNING] File encoding has not been set, using platform encoding Cp1252, i.e. b
uild is platform dependent!
[INFO] Compiling 1 source file to C:\MVN\consumerBanking\target\test-classes
[INFO]
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ consumerBanking ---
[INFO] Surefire report directory: C:\MVN\consumerBanking\target\surefire-reports


-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.companyname.bank.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.063 sec

Results :

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

[INFO]
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ consumerBanking ---
[INFO] Building jar: C:\MVN\consumerBanking\target\consumerBanking-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 14.406 s
[INFO] Finished at: 2015-09-27T17:58:06+05:30
[INFO] Final Memory: 14M/247M
[INFO] ------------------------------------------------------------------------
Run maven command using run as option.

Now, right click on App.java. Select Run As option. Select As Java Application.

You will see the result

Hello World!

Maven - NetBeans

NetBeans 6.7 and newer has inbuild support for Maven. In case of previous version, Maven plugin is available in plugin Manager. We're using NetBeans 6.9 in this example.

Some of features of NetBeans are listed below

  • You can run Maven goals from NetBeans.

  • You can can view the output of Maven commands inside the NetBeans using its own console.

  • You can update maven dependencies with IDE.

  • You can Launch Maven builds from within NetBeans.

  • NetBeans does the dependency management automatically based on Maven's pom.xml.

  • NetBeans resolves Maven dependencies from its workspace without installing to local Maven repository (requires dependency project be in same workspace).

  • NetBeans automatic downloads required dependencies and sources from the remote Maven repositories.

  • NetBeans provides wizards for creating new Maven projects, pom.xml

  • NetBeans provides a Maven Repository browser that enables you to view your local repository and registered external Maven repositories.

Following example will help you to leverage benefits of integrating NetBeans and Maven.

Open a maven project in NetBeans

  • Open NetBeans.

  • Select File Menu > Open Project option.

  • Select Project location, where a project was created using Maven. We've create a Java Project consumerBanking.See Maven Creating Project to see how to create a project using Maven.

Open a Maven project in NetBeans.

Now, you can see the maven project in NetBeans.Have a look at consumerBanking project Libraries and Test Libraries.You can see that NetBeans has added Maven dependencies to its build path.

Maven project in NetBeans.

Build a maven project in NetBeans

Now, Its time to build this project using maven capability of NetBeans.

  • Right Click on consumerBanking project to open context menu.

  • Select Clean and Build as option

Build a Maven project in NetBeans.

Maven will start building the project. You can see the output in NetBeans Console

NetBeans: Executing 'mvn.bat -Dnetbeans.execution=true clean install'
NetBeans:      JAVA_HOME=C:\Program Files\Java\jdk1.6.0_21
Scanning for projects...
------------------------------------------------------------------------
Building consumerBanking
   task-segment: [clean, install]
------------------------------------------------------------------------
[clean:clean]
[resources:resources]
[WARNING] Using platform encoding (Cp1252 actually)
to copy filtered resources, i.e. build is platform dependent!
skip non existing resourceDirectory C:\MVN\consumerBanking\src\main\resources
[compiler:compile]
Compiling 2 source files to C:\MVN\consumerBanking\target\classes
[resources:testResources]
[WARNING] Using platform encoding (Cp1252 actually)
to copy filtered resources, i.e. build is platform dependent!
skip non existing resourceDirectory C:\MVN\consumerBanking\src\test\resources
[compiler:testCompile]
Compiling 1 source file to C:\MVN\consumerBanking\target\test-classes
[surefire:test]
Surefire report directory: C:\MVN\consumerBanking\target\surefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.companyname.bank.AppTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.023 sec

Results :

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

[jar:jar]
Building jar: C:\MVN\consumerBanking\target\consumerBanking-1.0-SNAPSHOT.jar
[install:install]
Installing C:\MVN\consumerBanking\target\consumerBanking-1.0-SNAPSHOT.jar
to C:\Users\GB3824\.m2\repository\com\companyname\bank\consumerBanking\
1.0-SNAPSHOT\consumerBanking-1.0-SNAPSHOT.jar
------------------------------------------------------------------------
BUILD SUCCESSFUL
------------------------------------------------------------------------
Total time: 9 seconds
Finished at: Thu Jul 19 12:57:28 IST 2012
Final Memory: 16M/85M
------------------------------------------------------------------------

Run Application in NetBeans

Now, right click on App.java. Select Run File As option. You will see the result in NetBeans Console.

NetBeans: Executing 'mvn.bat -Dexec.classpathScope=runtime 
-Dexec.args=-classpath %classpath com.companyname.bank.App 
-Dexec.executable=C:\Program Files\Java\jdk1.6.0_21\bin\java.exe 
-Dnetbeans.execution=true process-classes 
org.codehaus.mojo:exec-maven-plugin:1.1.1:exec'
NetBeans:      JAVA_HOME=C:\Program Files\Java\jdk1.6.0_21
Scanning for projects...
------------------------------------------------------------------------
Building consumerBanking
   task-segment: [process-classes, 
   org.codehaus.mojo:exec-maven-plugin:1.1.1:exec]
------------------------------------------------------------------------
[resources:resources]
[WARNING] Using platform encoding (Cp1252 actually) 
to copy filtered resources, i.e. build is platform dependent!
skip non existing resourceDirectory C:\MVN\consumerBanking\src\main\resources
[compiler:compile]
Nothing to compile - all classes are up to date
[exec:exec]
Hello World!
------------------------------------------------------------------------
BUILD SUCCESSFUL
------------------------------------------------------------------------
Total time: 1 second
Finished at: Thu Jul 19 14:18:13 IST 2012
Final Memory: 7M/64M
------------------------------------------------------------------------

Maven - IntelliJ IDEA IDE Integration

IntelliJ IDEA has inbuild support for Maven. We're using IntelliJ IDEA Community Edition 11.1 in this example.

Some of features of IntelliJ IDEA are listed below

  • You can run Maven goals from IntelliJ IDEA.

  • You can can view the output of Maven commands inside the IntelliJ IDEA using its own console.

  • You can update maven dependencies within IDE.

  • You can Launch Maven builds from within IntelliJ IDEA.

  • IntelliJ IDEA does the dependency management automatically based on Maven's pom.xml.

  • IntelliJ IDEA resolves Maven dependencies from its workspace without installing to local Maven repository (requires dependency project be in same workspace).

  • IntelliJ IDEA automatic downloads required dependencies and sources from the remote Maven repositories.

  • IntelliJ IDEA provides wizards for creating new Maven projects, pom.xml

Following example will help you to leverage benefits of integrating IntelliJ IDEA and Maven.

Create a new project in IntelliJ IDEA

We'll import Maven project using New Project Wizard.

  • Open IntelliJ IDEA.

  • Select File Menu > New Project Option.

  • Select import project from existing model.

New Project in IntelliJ IDEA, step 1.
  • Select Maven option

New Project in IntelliJ IDEA, step 2.
  • Select Project location, where a project was created using Maven. We've create a Java Project consumerBanking.See Maven Creating Project to see how to create a project using Maven.

New Project in IntelliJ IDEA, step 3.
  • Select Maven project to import.

New Project in IntelliJ IDEA, step 4.
  • Enter name of the project and click finish.

New Project in IntelliJ IDEA, step 5.

Now, you can see the maven project in IntelliJ IDEA.Have a look at consumerBanking project external libraries.You can see that IntelliJ IDEA has added Maven dependencies to its build path under Maven section.

Maven project in IntelliJ IDEA.

Build a maven project in IntelliJ IDEA

Now, Its time to build this project using capability of IntelliJ IDEA.

  • Select consumerBanking project.

  • Select Buid menu > Rebuild Project Option

You can see the output in IntelliJ IDEA Console

4:01:56 PM Compilation completed successfully

Run Application in IntelliJ IDEA

  • Select consumerBanking project.

  • Right click on App.java to open context menu.

  • select Run App.main()

Maven project in IntelliJ IDEA.

You will see the result in IntelliJ IDEA Console.

"C:\Program Files\Java\jdk1.6.0_21\bin\java"
-Didea.launcher.port=7533 
"-Didea.launcher.bin.path=
C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 11.1.2\bin"
-Dfile.encoding=UTF-8 
-classpath "C:\Program Files\Java\jdk1.6.0_21\jre\lib\charsets.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\deploy.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\javaws.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\jce.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\jsse.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\management-agent.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\plugin.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\resources.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\rt.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\ext\dnsns.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\ext\localedata.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\ext\sunjce_provider.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\ext\sunmscapi.jar;
C:\Program Files\Java\jdk1.6.0_21\jre\lib\ext\sunpkcs11.jar
C:\MVN\consumerBanking\target\classes;
C:\Program Files\JetBrains\
IntelliJ IDEA Community Edition 11.1.2\lib\idea_rt.jar" 
com.intellij.rt.execution.application.AppMain com.companyname.bank.App
Hello World!
Process finished with exit code 0


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