Deploy a java application using jenkins

Introduction

In today’s fast-paced software development world, Continuous Integration and Continuous Deployment (CI/CD) streamline application delivery. In this blog, we’ll discuss how to deploy a Java-based application to an Apache Tomcat server using a CI/CD pipeline. We'll use Jenkins for automation, Maven for build management, and Git for version control.

Understanding the Tools

Git: Stores your application code and tracks changes.
Maven: Builds and manages Java projects by handling dependencies.
Jenkins: Automates the CI/CD process by integrating code building, testing, and deployment.
Tomcat: A popular server for hosting Java-based applications.

Real-Time Scenario

Imagine a software team working on an e-commerce web application. Every time a developer updates the product catalog, they push the changes to GitHub. Jenkins automatically:

Pulls the updated code.
Builds the application using Maven.
Perform the unit test using Maven.
Deploys the new version to Tomcat.

This process minimizes manual effort and ensures the application is always up-to-date.

Steps to Deploy a Java-Based Application Using CI/CD

STEP-1: Launch 2 EC2 Instances (Kernel 5.10)

Jenkins Server
Tomcat Server

STEP-2: Connect Jenkins server and Install Jenkins & GIT

#STEP-1: INSTALLING GIT
yum install git -y

#STEP-2: GETTING THE REPO (jenkins.io --> download -- > redhat)
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

#STEP-3: DOWNLOAD JAVA17 AND JENKINS
yum install java-17-amazon-corretto -y
yum install jenkins -y

#STEP-4: RESTARTING JENKINS (when we download service it will on stopped state)
systemctl start jenkins.service
systemctl status jenkins.service

Now copy the public-ip of your system and access it with 8080 port.

STEP-3: Now Install Deploy to container plugin

Go to Manage Jenkins » Plugins » Available Plugins » Deploy to container

STEP-4: Integrate Maven

Go to Manage Jenkins » tools and select maven

under the Maven Installations click on Add Maven

Name: mymaven

Version: default (3.9.9)

Now click on save

STEP-5: Create a Free Style Job

Go to Source Code Management and select Git and enter the repo-url (https://github.com/usubbu/one.git)

Go to Build Steps and select Invoke top-level Maven targets and select the Maven version as mymaven

Now enter the goal as clean package

Save the job and click on Build Now

If the build gets success, go to workspace and open the target folder, we will get war file

STEP-6: Deploy the application on Tomcat Server

connect the tomcat server and run the script to setup tomcat

Run the below script to setup tomcat

yum install java-17-amazon-corretto -y
wget https://dlcdn.apache.org/tomcat/tomcat-9/v9.0.98/bin/apache-tomcat-9.0.98.tar.gz
tar -zxvf apache-tomcat-9.0.98.tar.gz
sed -i '56  a\<role rolename="manager-gui"/>' apache-tomcat-9.0.98/conf/tomcat-users.xml
sed -i '57  a\<role rolename="manager-script"/>' apache-tomcat-9.0.98/conf/tomcat-users.xml
sed -i '58  a\<user username="tomcat" password="admin@123" roles="manager-gui, manager-script"/>' apache-tomcat-9.0.98/conf/tomcat-users.xml
sed -i '59  a\</tomcat-users>' apache-tomcat-9.0.98/conf/tomcat-users.xml
sed -i '56d' apache-tomcat-9.0.98/conf/tomcat-users.xml
sed -i '21d' apache-tomcat-9.0.98/webapps/manager/META-INF/context.xml
sed -i '22d'  apache-tomcat-9.0.98/webapps/manager/META-INF/context.xml
sh apache-tomcat-9.0.98/bin/startup.sh

Remember the tomcat credentials

username**:** tomcat
password**:** admin@123

If you wish to modify, change the credentials on above script also.

Now access the tomcat dashboard with public-ip of tomcat server with 8080 port.

Now go to Manager App and enter the credentials, You will get the Tomcat Web Application Manager dashboard.

STEP-7: Integrate Tomcat with Jenkins

Configure the Jenkins job and select Post Build Actions and select Deploy war/ear to a container

WAR/EAR file: target/*.war

context path: swiggy

and click on add container and select Tomcat 9.x Remote

Now add the tomcat credentials, click on Add select Jenkins

Now click on Add and select the credentials and enter the tomcat url

Now save the job and click on Build Now, If the build gets success then our application will be deployed on tomcat successfully.

The build is success, Now lets refresh the tomcat page and we will see swiggy app is running

Open the swiggy app and check the output.

To automate the delivery process, we can also implement Webhooks!.

Best Practices

Use a separate staging environment for testing deployments before pushing to production.
Automate testing as part of the CI/CD pipeline to catch bugs early.
Secure your Jenkins and Tomcat configurations to prevent unauthorized access.

Conclusion

By automating deployment with CI/CD, you save time, reduce errors, and deliver features faster. Deploying Java applications to Tomcat with tools like Jenkins and Maven is straightforward when done step-by-step. Start building your pipeline today to experience the power of automation.

If you love stories that inspire learning, growth, and productivity, consider subscribing for more! If this article added value to your journey, your support would mean the world to me — only if it’s within your means. Let’s stay connected on LinkedIn too. Thank you for reading 💕

Deploy a Java Application using Jenkins