Jenkins and Maven: Building and Continuous Integration for Java EE Applications

When developing Java Enterprise Edition (Java EE) applications, choosing the right tools for building and continuous integration is crucial. Both Jenkins and Maven serve vital roles in this process, albeit for different purposes. This guide delves into the unique features and benefits of each, highlighting why you should use both in your team's workflow.

Why Maven?

Maven is not just a build tool; it is a comprehensive framework that supports numerous tasks such as building, releasing, and managing Java projects. Below, we highlight some of the key features that make Maven indispensable for Java EE application development.

Parent-Child Project Structure

When your project is divided into multiple sub-projects, Maven streamlines the replication and reuse of build configurations. The parent-child relationship allows shared dependencies to be managed centrally. This setup ensures that all sub-projects are consistently built with the latest dependencies, reducing the potential for version mismatches and conflicts.

Dependent JAR Management

Managing dependent JAR files can be a cumbersome task, especially when dealing with complex projects. Maven automates the process of downloading and managing dependencies. If a project relies on a JAR that also depends on additional JARs, Maven will automatically download all required JARs, including their transitive dependencies. This ensures that your project is always built with the correct set of dependencies, without manual intervention.

Scope Management

Maven offers the scope attribute to manage the inclusion of JAR files during different phases of the build cycle. For instance, certain JARs may be needed only for compilation and not for packaging, or for unit testing purposes, such as JUnit, without affecting the final WAR file due to size or licensing constraints. This flexibility ensures that your deployment artifacts are as lean as possible while still having access to necessary libraries during development.

Why Jenkins?

While Maven focuses on building, Jenkins excels in continuous integration (CI), ensuring that code changes are tested and validated automatically. It integrates seamlessly with version control systems like Git, making it possible to automatically run the build, test, and deployment processes with every commit.

Automated Builds and Integrations

Jenkins can be triggered in several ways, ensuring that the build process is always up-to-date. You can manually initiate a build, have Jenkins monitor the code repository for new commits, or even schedule periodic builds based on time intervals. This ensures that the latest code is always built and validated, reducing the risk of introducing bugs into your production environment.

CI Workflow

The CI process with Jenkins includes a series of steps:

Check out the latest code from the repository using Git. Invoke Maven or Ant to build the WAR file. Deploy the WAR file to the server. Run automated functional and non-functional tests. Provide the results, indicating the success or failure of the build and tests.

This workflow ensures that any changes in the codebase are quickly and efficiently validated, promoting a robust development and testing environment.

Need Both!

While Maven and Jenkins serve distinct purposes, they complement each other in the development lifecycle. Maven ensures the successful building and packaging of your application, while Jenkins automates the continuous integration process, enabling frequent and reliable builds and tests.

Maven is used for the core build tasks, whereas Jenkins performs the continuous integration tasks. When Maven builds the project, it produces the necessary artifacts, which are then managed by Jenkins for testing and deployment. This integration ensures that there is no manual intervention in the build and test process, making the development cycle more efficient and robust.

In conclusion, combining Maven for building and Jenkins for continuous integration is the best way to streamline the development and deployment process for Java EE applications. By leveraging the strengths of both tools, your team can deliver high-quality applications with fewer bugs and issues, ultimately improving the overall development experience.