Ready to supercharge your DevOps journey? If you’re diving into CI/CD for the first time or looking to automate your Maven builds with Jenkins, you’re in the right place! In this post, I’ll take you step-by-step through the entire process—from coding in Eclipse, pushing your project to GitHub, to setting up Jenkins for seamless automated builds and tests. Let’s turn your development workflow into a powerful, automated machine!
<h2>STEP-BY-STEP WORKFLOW</h2>
<h3>Step 1: Download &amp; Set Up Eclipse</h3>
<ol>
<li>Go to <a href="https://www.eclipse.org/downloads/packages/" target="_blank" rel="noopener nofollow">https://www.eclipse.org/downloads/packages/</a></li>
<li>Download Eclipse IDE for Java Developers</li>
<li>Install and open Eclipse.</li>
<li>Select a workspace folder.</li>
</ol>
<h3>Step 2: Create Maven Project in Eclipse</h3>
We will be using a sample calculator example in eclipse for our understanding and later on we will have test cases for this calculator
<ol>
<li>File → New → Maven Project</li>
<li>Choose:
<ul>
<li>Group Id: <code>com.example</code></li>
<li>Artifact Id: <code>calculator</code></li>
</ul>
</li>
</ol>
Your Eclipse project directory structure will look something like this:
<pre><code>calculator/
├── src/
│ ├── main/
│ │ └── java/
│ │ └── com/example/Calculator.java
│ └── test/
│ └── java/
│ └── com/example/CalculatorTest.java
├── pom.xml
</code></pre>
<h3>Step 3: Write Calculator Code</h3>
<ol>
<li>Go into <code>src/main/java/com/example/Calculator.java</code> file</li>
<li>Paste the below code there</li>
</ol>
<pre><code class="language-java">package com.example;

public class Calculator {
 public int add(int a, int b) {
 return a + b;
 }
 public int subtract(int a, int b) {
 return a - b;
 }
 public int multiply(int a, int b) {
 return a * b;
 }
 public int divide(int a, int b) {
 if (b == 0) throw new ArithmeticException(&quot;Cannot divide by zero&quot;);
 return a / b;
 }
}
</code></pre>
**Note:**Your file name and the class name in the code must be the same.
<h3>Step 4: Write JUnit Test Cases</h3>
Go into <code>src/test/java/com/example/CalculatorTest.java</code> and paste the below code into the file.
<pre><code class="language-java">package com.example.calculator;

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;

public class CalculatorTest {
 Calculator calc = new Calculator();

 @Test
 public void testAdd() {
 assertEquals(8, calc.add(5, 3));
 }

 @Test
 public void testSubtract() {
 assertEquals(2, calc.subtract(5, 3));
 }

 @Test
 public void testMultiply() {
 assertEquals(15, calc.multiply(5, 3));
 }

 @Test
 public void testDivide() {
 assertEquals(2, calc.divide(6, 3));
 }
}
</code></pre>
<h3>Step 5: Add JUnit Dependency in pom.xml</h3>
Paste the below code into the <code>pom.xml</code>
<pre><code class="language-xml">&lt;project xmlns=&quot;http://maven.apache.org/POM/4.0.0&quot;
 xmlns:xsi=&quot;http://www.w3.org/2001/XMLSchema-instance&quot;
 xsi:schemaLocation=&quot;http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd&quot;&gt;

 &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
 &lt;groupId&gt;com.example&lt;/groupId&gt;
 &lt;artifactId&gt;calculator&lt;/artifactId&gt;
 &lt;version&gt;0.0.1-SNAPSHOT&lt;/version&gt;
 &lt;packaging&gt;jar&lt;/packaging&gt;
 &lt;name&gt;calculator&lt;/name&gt;
 &lt;url&gt;http://maven.apache.org&lt;/url&gt;

 &lt;properties&gt;
 &lt;project.build.sourceEncoding&gt;UTF-8&lt;/project.build.sourceEncoding&gt;
 &lt;/properties&gt;

 &lt;!-- Here we are adding the dependencies of JUnit into the project --&gt;
 &lt;dependencies&gt;
 &lt;!-- JUnit 5 --&gt;
 &lt;dependency&gt;
 &lt;groupId&gt;org.junit.jupiter&lt;/groupId&gt;
 &lt;artifactId&gt;junit-jupiter-api&lt;/artifactId&gt;
 &lt;version&gt;5.12.1&lt;/version&gt;
 &lt;scope&gt;test&lt;/scope&gt;
 &lt;/dependency&gt;
 &lt;/dependencies&gt;

 &lt;build&gt;
 &lt;plugins&gt;
 &lt;plugin&gt;
 &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
 &lt;artifactId&gt;maven-compiler-plugin&lt;/artifactId&gt;
 &lt;version&gt;3.8.1&lt;/version&gt;
 &lt;configuration&gt;
 &lt;source&gt;17&lt;/source&gt;
 &lt;target&gt;17&lt;/target&gt;
 &lt;/configuration&gt;
 &lt;/plugin&gt;
 &lt;/plugins&gt;
 &lt;/build&gt;

&lt;/project&gt;
</code></pre>
<h2>Step 6. Launch &amp; Set Up EC2 Instance</h2>
<ol>
<li>
Launch Ubuntu EC2 Instance on AWS.
</li>
<li>
Open the following ports in your Security Group:
<ul>
<li>Port <code>22</code> (SSH)</li>
<li>Port <code>80</code> (HTTP) , 0.0.0.0/0</li>
<li>Port <code>8080</code> (Custom TCP), 0.0.0.0/0</li>
<li>Port <code>443</code> (HTTPS)</li>
</ul>
</li>
<li>
SSH into the instance:
Go to the instance, connect, copy the ssh command and paste in your terminal.
There run these commands:
</li>
</ol>
<ul>
<li>Install Apache2:</li>
</ul>
<pre><code>sudo apt update
sudo apt upgrade
sudo apt install apache2
</code></pre>
If you are done, paste
<pre><code>http:your-ec2-public url 
</code></pre>
If there apache default page shows up means your apache2 is all set up.
Note : Replace ec2-publicurl with your EC2 instance’s public DNS or IP
<ul>
<li>Install Jenkins:</li>
</ul>
Copy these commands ony by one
<pre><code>sudo wget -O /etc/apt/keyrings/jenkins-keyring.asc \
 https://pkg.jenkins.io/debian/jenkins.io-2023.key
</code></pre>
<pre><code>echo &quot;deb [signed-by=/etc/apt/keyrings/jenkins-keyring.asc]&quot; \
 https://pkg.jenkins.io/debian binary/ | sudo tee \
 /etc/apt/sources.list.d/jenkins.list &gt; /dev/null
</code></pre>
<pre><code>sudo apt-get update
</code></pre>
<pre><code>sudo apt install fontconfig openjdk-21-jre
</code></pre>
<pre><code>sudo apt-get install Jenkins
</code></pre>
After installing these, paste
<pre><code>http:public url of ec2 :8080
</code></pre>
Note : Replace ec2-publicurl with your EC2 instance’s public DNS or IP.
You will see the jenkins page.
Unlock Jenkins: If the Jenkins page is locked, retrieve the initial admin password:
Note the file path shown on the Jenkins page (e.g., /var/lib/jenkins/secrets/initialAdminPassword).
In your EC2 SSH terminal, run:
<pre><code>sudo cat /var/lib/jenkins/secrets/initialAdminPassword
</code></pre>
Copy the password, paste it into the Jenkins setup page, and click Continue.
<ul>
<li>Install Docker:</li>
</ul>
<pre><code>sudo apt update
sudo apt install docker.io -y
</code></pre>
<h2>Step 7: Push Code to GitHub</h2>
Upload the entire Eclipse project folder in github after making a public repo.
Let’s say its name is junit-testing and for your ease upload only the folder names <code>src</code> and pom.xml`.
Steps to add a webhook
<ol>
<li>Go to Settings of this repo.</li>
<li>Navigate to Webhooks in the left sidebar and find Add webhook there. Add payload URL as:</li>
</ol>
<pre><code>http://ec2-publicurl:8080/github-webhook/
</code></pre>
Note : Replace ec2-publicurl with your EC2 instance’s public DNS or IP
<ol start="3">
<li>Set the Content type as <code>application/json</code> and the below settings as:</li>
</ol>
<img src="https://media.daily.dev/image/upload/s--dpexSHUR--/f_auto/v1747224287/ugc/content_53a6bcbd-a137-4aee-99ae-b6fce93e98d2?_a=BAMClqUq0" alt="image">
You are done with github.
<h3>Step 8: Jenkins Pipeline Setup</h3>
<ol>
<li>Open Jenkins dashboard.</li>
<li>Select new item. Choose pipeline.</li>
<li>In general select github project enter your github repo link there.</li>
<li>In triggers, choose GitHub hook trigger for GITScm polling.</li>
<li>In pipeline, under definition drop down choose pipeline script. Paste this:</li>
</ol>
<pre><code class="language-groovy">pipeline {
 agent {
 docker {
 image &#x27;maven:3.8.5-openjdk-17&#x27;
 }
 }

 stages {
 stage(&#x27;Clone Repository&#x27;) {
 steps {
 git branch: &#x27;main&#x27;, url: &#x27;https://github.com/YOUR-USERNAME/JavaMaven.git&#x27;
 }
 }

 stage(&#x27;Build&#x27;) {
 steps {
 sh &#x27;mvn -DskipTests clean install&#x27;
 }
 }

 stage(&#x27;Test&#x27;) {
 steps {
 sh &#x27;mvn test&#x27;
 }
 }
 }
}
</code></pre>
Note: Make sure to update the GitHub URL in script with your GitHub repo URL.
Now run the build and you are good to go
<h2>Final Outcome</h2>
Once you run the Jenkins build:
Check the Jenkins build console output to verify that the code was pulled, built, and all 4 JUnit tests passed successfully.

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DevOps

Learn to automate your DevOps workflows with Jenkins by following a detailed guide, from setting up Eclipse and creating a Maven project to configuring Jenkins for automated builds and JUnit testing. This includes launching an EC2 instance on AWS, pushing your project to GitHub, setting up webhooks, and configuring a Jenkins pipeline.

Mastering CI/CD: Automate Maven Builds and JUnit Tests with Jenkins from Eclipse to GitHub