BCSL657D Program 4

4. Practical Exercise: Build and Run a Java Application with Maven, Migrate the Same Application to Gradle.

Step 1: Creating a Maven Project

You can create a Maven project using the mvn command (or through your IDE, as mentioned earlier). But here, I’ll give you the essential pom.xml and Java code.

• I’m Using Command Line:
  • To create a basic Maven project using the command line, you can use the following command:

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

Step 2: Open The pom.xml File

• You can manually navigate the project folder named call maven-example and open the file pom.xml and copy the below code and paste it then save it.
• In case if you not getting project folder then type command in your cmd.
  • cd maven-example – is use to navigate the project folder.
  • notepad pom.xml – is use to open pom file in notepad.

<?xml version="1.0" encoding="UTF-8"?>
<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.example</groupId>
    <artifactId>maven-example</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Step 3: Open Java Code (App.java) File

• Open a file App.java inside the src/main/java/com/example/ directory.
• After opening the App.java copy the below code and paste it in that file then save it.

package com.example;

public class App {
    public static void main(String[] args) {
        System.out.println("Hello, Maven");
        System.out.println("This is the simple realworld example....");

        int a = 5;
        int b = 10;
        System.out.println("Sum of " + a + " and " + b + " is " + sum(a, b));
    }

    public static int sum(int x, int y) {
        return x + y;
    }
}

Note: before building the project make sure you are in the project folder if not navigate the project folder type command in your command prompt cd maven-example.

Step 4: Run the Project

To build and run this project, follow these steps:

• Open the terminal in the project directory and run the following command to build the project.

mvn clean install

• Run the program with below command:

mvn exec:java -Dexec.mainClass="com.example.App"

Step 5: Migrate the Maven Project to Gradle

1. Initialize Gradle: Navigate to the project directory (gradle-example) and run:

gradle init

• It will ask Found a Maven build. Generate a Gradle build from this? (default: yes) [yes, no]
  • Type Yes
• Select build script DSL:
  • 1: Kotlin
  • 2: Groovy
  • Enter selection (default: Kotlin) [1..2]
    • Type 2
• Generate build using new APIs and behavior (some features may change in the next minor release)? (default: no) [yes, no]
  • Type No

2. Navigate the project folder and open build.gradle file then add the below code and save it.

plugins {
    id 'java'
}

group = 'com.example'
version = '1.0-SNAPSHOT'

repositories {
    mavenCentral()
}

dependencies {
    testImplementation 'junit:junit:4.12'
}

task run(type: JavaExec) {
    main = 'com.example.App'
    classpath = sourceSets.main.runtimeClasspath
}

Step 6: Run the Gradle Project

• Build the Project: In the project directory (gradle-example), run the below command to build the project:

gradlew build

• Run the Application: Once the build is successful, run the application using below command:

gradlew run

Step 7: Verify the Migration

• Compare the Output: Make sure that both the Maven and Gradle builds produce the same output:
  • Maven Output:

Hello, Maven
This is the simple realworld example....
Sum of 5 and 10 is 15

• Gradle Output:

Hello, Maven
This is the simple realworld example....
Sum of 5 and 10 is 15