Building a Java Application from GitHub using Jenkins | Run java program from Jenkins

Building a Java application using Jenkins and GitHub involves setting up a continuous integration (CI) pipeline that fetches the source code from a GitHub repository, builds the application, runs tests, and possibly deploys it. Here are the general steps to achieve this:

Prerequisites:
GitHub repository: The Java application's source code hosted on GitHub.
Jenkins: Jenkins installed and configured on your server or local machine.

Steps:

1. Set up a Jenkins job:
Create a new Jenkins job: In Jenkins, create a new freestyle project or a pipeline.
Configure source code management:
In the Jenkins job configuration, set up the GitHub repository URL where your Java application code resides.
Add credentials if your repository requires authentication.

2. Install necessary tools in Jenkins:
Install Java: Ensure Java Development Kit (JDK) is installed on the Jenkins server or configure Jenkins to use an installed JDK.
Plugins: GitHub Integration Plugin.

3. Build and Test:
Set up build steps: Define build steps in Jenkins, typically involving commands to compile and build the Java application.
-For Java: javac Test.java
-For Maven: mvn clean install

Add test steps: Run standalone Java and unit tests and any other necessary testing procedures.
To run Java program : java Test (class fileName)
For Maven: mvn test

4. Configure Deployment (if required):
Deploy to a server: If your project involves deployment to a server, set up deployment steps within Jenkins. This could involve copying the built artifacts to a specific location.

5. Setup Webhooks (Optional):
Set up GitHub Webhooks: To trigger Jenkins builds automatically upon code changes, set up webhooks in the GitHub repository to notify Jenkins when changes occur.

6. Save and run the Jenkins job:
Save your Jenkins job configuration.
Manually run the job: Test your Jenkins job by manually triggering a build to ensure everything is set up correctly.

7. Monitor and Troubleshoot:
Monitor Jenkins Console Output: Check the Jenkins job's console output for any errors or issues during the build process.
Troubleshoot and Iterate: If there are any problems, adjust your Jenkins job configuration and retest until the process runs smoothly.