Step-By-Step Process to build Java application in Jenkins?

Step 1: Launch an Instance

Launch EC2 Instances with specifications AMI Amazon Linux 2 kernel, port number 22,8080 for Jenkins because our Jenkins runs on port 8080

Now, connect it to the instance with SSH command.

Step 2: Install Java and Jenkins

Before going to install jenkins packages we need to install jenkins runtime that is JAVA. Without java jenkins cannot run. Install by using following command

sudo yum -y install java-17*

Now install jenkins packages from official website or follow below commands

sudo wget -O /etc/yum.repos.d/jenkins.repo \
    https://pkg.jenkins.io/redhat-stable/jenkins.repo
sudo rpm --import https://pkg.jenkins.io/redhat-stable/jenkins.io-2023.key
sudo yum upgrade

After installing packages now install jenkins by using following command

sudo yum -y install jenkins

Now start and enable our jenkins by using following commands

sudo systemctl start jenkins
sudo systemctl enable jenkins
sudo systemctl status jenkins 

While we check jenkins status it gives administration password. Copy that password and paste it on jenkins unlock page.

In Above figure shows that highlighted words is the administration password.

Now, copy paste the public IP address along with port 8080 and unlock Jenkins with admin password.

Official page of Jenkins

Step 3: Creating Jobs

Now click on new item, enter item name it is like title and select freestyle.

Create a clone-build-job for cloning the repo and build the application related code to build with the help of triggers/plugins.

We need to install maven integration plugin to avoid manual process.

Manage Jenkins –> available plugins –> maven integration

Now in source code management give GitHub URL to clone from GitHub account of the application.

Now in build steps there is a option Invoke top-level Maven targets in that select maven integration

In build steps select execute shell in that execute shell write a script to install tomcat to host our java application

Now we need to install another plugin to move .war files, for that install a plugin called Deploy to container.

Manage Jenkins –> Available –> deploy to container

Now in Post Build Actions select Deploy war/ear to a container

In this give this path to execute our war file **/*.war

War/ear files to deploy. Relative to the workspace root. You can also specify Ant-style GLOBs, like “**/*.war”

In Containers section add credentials to tomcat and provide tomcat URL

Now on click on save. Now our job was ready to build and finally click on build now

Now copy Public IP and browse it along with port 8080 you can see tomcat page in that tomcat page our application was hosted.

In the software development lifecycle, building and testing applications are basic steps toward ensure code quality and dependability. Jenkins, an open-source automation server, plays a vital role in automating these cycles, especially for Java applications. Java, being one of the most generally utilized programming languages, benefits extraordinarily from Jenkins’ capacities in automating builds, tests, and deployments.

Automating the build cycle of Java applications in Jenkins streamlines out the development work process, allowing developers to zero in a larger number of on composing code as opposed to manually taking care of build tasks. By setting up Jenkins responsibilities to construct Java projects, developers can accomplish continuous integration, where changes are routinely integrated into the fundamental codebase and confirmed through automated tests.

This article will dig into the most common way of building Java applications in Jenkins, covering the setup of Jenkins jobs, setup of configuration steps, and monitoring of build results. We’ll explore the fundamental stages, terminologies, and best practices associated with utilizing Jenkins for Java application development. Through step by step guidelines, examples, and FAQs, developers will acquire a complete comprehension of how to use Jenkins for building Java applications really.