top of page
hand-businesswoman-touching-hand-artificial-intelligence-meaning-technology-connection-go-

Introduction to Maven and POM.XML

What is Maven

Maven is a build automation tool used primarily for java projects. Maven can also be used to build and manage projects written in C#, Ruby and other languages.


Download and Install Apache Maven

System requirements

JDK

Maven 3.3+ require JDK 1.7 or above to execute

Memory

No minimum requirement

Disk

Approx. 10MB is required for Maven installation itself. In addition to that, additional disk space will be used for your local Maven repository

Operating System

No minimum requirement. Start Up scripts are included as Shell scripts and Windows batch files

We need to follow these four steps to install Maven on our machine

  1. Download MAVEN zip file & Extract

  2. Setup MAVEN bin path

  3. Set MAVEN_HOME

  4. Verify MAVEN Installation

Step 1. Download MAVEN zip file & Extract

i) To download Maven, visit following website

https://maven.apache.org/download.cgi


ii) Click the Binary zip link from second row below


iii) After download is complete, extract the Maven archive to C:\Program Files

Open above apache-maven-3.8.6 folder


You can see bin folder is there, which is the important folder. Copy that path. Here the path link is ( C:\Program Files\Maven\apache-maven-3.8.6 ). Now we are going to set MAVEN bin path.



Step 2. Setup MAVEN bin path


i) Open Environmental Variables window from Start menu.

ii) Click the Edit the Systems Environment Variables option. Then System Properties window will open.

iii) Click on the Environment Variables tab.


iv) Select Path option under the System Variables section. Click on Edit button.

v) - Click on New button.

- Paste the path to MAVEN bin folder which we have already copied in previous step.

( C:\Program Files\Maven\apache-maven-3.8.6 )

- Click OK button.


vi) Click OK button in Environment Variables window


Now we are done with setting up MAVEN bin path.

Next we are going to set MAVEN_HOME.


Step 3. Set MAVEN_HOME


i) Click New button (highlighted) under the System Variables section to add new System Environment variable.

v) Enter variable name as MAVEN_HOME.

Variable value is the path to the Maven bin folder (which we have already copied in previous steps C:\Program Files\Maven\apache-maven-3.8.6 ).

Click OK to save the new system variable.


Step 4. Verify MAVEN Installation


In command prompt use the following command to check whether Maven is installed correctly.

It will show the version of Maven installed in your machine. So we are done with installing Maven successfully in our machine.


How to create a Maven project in Eclipse IDE

  1. Open Eclipse IDE.

  2. Click on File => New => Project

OR

Create a project link


3. Click on the arrow near Maven, and it will show more options.


4. Select Maven Project option. Click on Next button.


5. Select the check boxes as shown and click Next button.


6. Fill in Group-Id, Artifact-Id and Name and click on Finish button.


7. We can see our project in Package Explorer.


Maven projects are configured using a POM (Project Object Model), which is stored in pom.xml file.


The directory structure of normal Maven Project has following directory entries.

Directory Name

Purpose

Project name

Contains the pom.xml and all the sub-directories.

src/main/java

Contains the deliverable java source code for the project.

src/main/resources

Contains the deliverable resources for the project, such as property file.

src/test/java

Contains the testing java source code (eg. JUnit or TestNg test cases) for the project.

src/test/resources

Contains resources necessary for the project.


Diagrammatical representation of directory structure of Maven project



POM.XML plays an important role in Maven project.



What is POM.XML in Maven


The POM file is the main artifact of Maven.

Most projects depend on external jars to build and run correctly. Whenever you are testing any app or website using an automation tool, you need to download the required jars and add inside lib folder. Instead of doing it manually , if you use maven, POM.XML will be generated and it will automate the process of adding required jars for your project. For that you need to add required dependencies and plugins in pom.xml and then the jars you configured there will be added to your local repositories.



POM stands for Project Object Model, which is the fundamental unit of work in Maven. It is an XML file that contains information about the project and configuration details used by Maven to build the project such as dependencies, build directory, source directory, goals, plugins etc.


When 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.


Before creating POM, we should first decide the project group (group-id), it's name (artifact-id) and it's version as these attributes help in uniquely identifying the project in repository.


Whenever you created a Maven project, POM.XML gets created as shown below,

If we open this pom.xml, it will be like below. This is called as Minimal POM.

The Minimal POM will inherit all the configurations from the Super POM. One main advantage of the POM hierarchy in maven is that we can extend and override the configuration inherited from the top.


Minimum required elements of POM are as follows

Elements

Description

Project

This is the root of descriptor

Model Version

Model version is the version of project descriptor your POM conforms to. It needs to be included and is set. The value 4.0.0 just indicated that it is compatible Maven 3

group-Id

A universally unique identifier for a project

artifact-Id

The id of the artifacts in respective project

version

The version of the artifacts under the specified group

Super POM


Super POM is Maven's default POM. All POMs inherit from a parent or default . This base POM is known as Super POM. It defines all the default configurations. Hence, even the simplest form of a POM file will inherit all the configurations defined in the Super POM file.


Effective POM


Effective POM combines all the default settings from the super POM file and the configuration defined in our application POM.

To view the effective pom from command line, pass the following command

OR


In console under the tab "Effective console" we can see the effective pom.


Additional Elements in POM.XML


Let’s see additional elements in pom.xml

Elements

Description

packaging

Defines packaging type such as jar, war etc.

name

Defines name of the maven project

url

Defines URL of the project

dependencies

Defines dependencies for this project

dependency

Defines a dependency. It is used inside dependencies

plugins

The list of plugins to be used

plugin

The Group Id of the plugin in repository

scope

Defines scope of the maven project. It can be compile, provided, runtime, test and system

properties

Value placeholders, the values are accessible anywhere within a POM by using the notation ${x}, where x is property

Basic structure of POM.XML


Following is the basic structure of pom.xml

We can download all the required dependencies and plugins from Central Maven repository.


Consider the following example of pom.xml

This is pom.xml file for the project sampleMavenProject.

Here I have defined the value for cucmber.version using properties element and used it twice here.

Copied cucumber-java and cucumber-junit dependencies and maven-compiler-plugin form maven central repository.

Whenever you update maven project all the jars will get downloaded to your project.



Conclusions:


Maven provides pom.xml, where we can manage dependencies easily. Dependency management in previous days was the most complicated mess for handling complex projects. The quick project set up is achieved through POM files. The way it works is that it allows you to define dependencies to external libraries that your project needs, and when you use Maven to build your project it will fetch these libraries from the web (external repositories) and add them to your built project. So it's an automatic handling of dependencies.





153 views0 comments
bottom of page