Java : Using Maven to build and compile your HelloWorld application

Install java, set the JAVA_HOME to the java installation path and 
PATH variable to existing PATH + %JAVA_HOME%\bin folder.

Install MAVEN and set MAVEN_HOME to the maven installation path and
PATH variable to existing PATH + %MAVEN_HOME%\bin folder.

(BASE_FOLDER)/com/example

App.java

package com.example;

public class App {

    public static void main(String[] args) {

        System.out.println("Hello, World!");

    }

}

In BASE_FOLDER

javac com/example/App.java

java com.example.App

Hello, World!

https://maven.apache.org/ 

Maven is a build tool for java projects. ......

Creating a MAVEN pom.xml file.

<project xmlns="http://apache.org" xmlns:xsi="http://w3.org"

  xsi:schemaLocation="http://apache.org http://apache.org">

<modelVersion>4.0.0</modelVersion>  

 

<groupId>com.example</groupId>

<artifactId>myapp1</artifactId>

<version>1.0-SNAPSHOT</version>

<properties>

        <maven.compiler.source>17</maven.compiler.source>

        <maven.compiler.target>17</maven.compiler.target>

    </properties>

<build>

        <plugins>

            <plugin>

<groupId>org.codehaus.mojo</groupId>

                <artifactId>exec-maven-plugin</artifactId>

                <version>3.1.0</version>

                <configuration>

                    <mainClass>com.example.App</mainClass>

                </configuration>

            </plugin>

        </plugins>

    </build>

</project>

The Root and Metadata Elements

<project xmlns="http://apache.org" xmlns:xsi="http://w3.org" xsi:schemaLocation="http://apache.org http://apache.org">

<project>: The root tag that encloses the entire Maven configuration.

xmlns and xsi: These tell your code editor and Maven where to find the rules (schemas) for validating the XML structure. 

<modelVersion>4.0.0</modelVersion>  

<modelVersion>: Defines the version of the POM structure layout. Version 4.0.0 is the mandatory standard for Maven 2 and Maven 3.

Project Coordinates (The GAV)

These three elements uniquely identify your project across the Java ecosystem.

<groupId>com.example</groupId>

<groupId>: The organization or package name. It usually follows reverse domain name rules (like com.companyname).

<artifactId>myapp1</artifactId>

<artifactId>: The specific name of your project. This becomes the actual name of your compiled JAR file.

<version>1.0-SNAPSHOT</version>

<version>: The current version of your app. -SNAPSHOT means it is a work-in-progress development version.

<properties>
    <maven.compiler.source>17</maven.compiler.source>
    <maven.compiler.target>17</maven.compiler.target>
</properties>

<properties>: A section used to define variables or settings.

source: Tells Maven your source code is written using Java 17 features.

target: Tells Maven to compile bytecode that is fully compatible with Java 17 runtimes.

<build>: Contains configurations that manage how your project compiles, runs, and bundles.

<plugins>: A wrapper tag holding the list of external tools/extensions Maven will use. 

        <plugin>

            <groupId>org.codehaus.mojo</groupId>

            <artifactId>exec-maven-plugin</artifactId>

            <version>3.1.0</version>

• <plugin>: Declares an external tool to use.
• groupId & artifactId: Points Maven to download the official plugin that can execute Java programs.
• version: Locks down the version of the plugin so your build remains stable over time.

            <configuration>

                <mainClass>com.example.App</mainClass>

            </configuration>

• <configuration>: Passes custom settings directly to the plugin.
• <mainClass>: Tells the plugin exactly where your public static void main method lives so it knows what to run.

See what below command does

mvn archetype:generate -DgroupId=com.example -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false