Syntax: mvn archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4 -DinteractiveMode=false

Explanation: For beginners,
Only two things are of concern:
1) Group ID: This will be our package name.
2) Artifact ID: This is our project name (mvn-cmd)

At the source folder of the project:
1) src/ 
It contains two folders:
1.1) main/ 
It is used to create codes in java
1.2) test/
It is used to create JUnit Test cases
2) pom.xml 
Pom.xml is the mail build file of the maven!

Go to /src/main/java/pkg1
NOTE: pkg1 is the package name we defined while creating the project.
Always include package name in the code.
Modify the app.java file 
Rename to the file name you want.

Before start building a project, it is necessary to delete old configuration files.
mvn clean command is used to delete the target/ folder.

This command is used to check whether the source code we wrote in java file is correct syntactically or not.

This work is tricky. 
You must know how to create JUnit Test cases.
You need to define the Unit Test cases in /src/test/pkg1

Checks the Maven Configuration in pom.xml file
Creates the project build.
Creates jar file in target/ folder which can be deployed

Maven Site command is used to create GUI reports
It creates reports in format of web pages in HTML+CSS format.
Site Reports are stored in /target/site