WAR versus EAR Packaging Comparison | Generated by AI
Overview
In Java EE (now Jakarta EE), WAR (Web Archive) and EAR (Enterprise Archive) are standard packaging formats for deploying applications to application servers like Tomcat, WildFly, or GlassFish. WAR is focused on web-tier components, while EAR bundles multiple modules for full enterprise applications. Below is a detailed comparison.
| Aspect | WAR (Web Archive) | EAR (Enterprise Archive) |
|---|---|---|
| Purpose | Deploys web applications (e.g., servlets, JSPs, static content) as a single unit for web-tier functionality. | Deploys enterprise applications by packaging multiple sub-modules (e.g., WARs, EJB JARs) for multi-tier, distributed systems. |
| Contents | - Web app files: JSPs, HTML/CSS/JS, servlets. - Libraries: WEB-INF/lib JARs. - Deployment descriptor: web.xml (optional in modern versions). |
- Multiple modules: WARs, EJB JARs, client JARs. - Shared libraries. - Deployment descriptor: application.xml. - RARs for resource adapters (optional). |
| Structure | - Root: static resources (e.g., index.html). - WEB-INF/: classes, lib, web.xml. |
- Root: META-INF/application.xml. - Subdirectories for each module (e.g., myapp.war, myejb.jar). |
| File Extension | .war | .ear |
| Deployment Scope | Single module; deploys to web containers (e.g., Tomcat) or full app servers. | Multi-module; deploys only to full application servers (e.g., JBoss, WebLogic) for enterprise features like transactions. |
| Size & Complexity | Smaller and simpler; ideal for standalone web apps. | Larger and more complex; supports modularity and shared resources across modules. |
| Use Cases | Web portals, REST APIs, simple services (e.g., Spring Boot web apps packaged as WAR). | Complex enterprise systems (e.g., banking apps with web UI + business logic + data access). |
| Dependencies | Relies on container for web services; no built-in EJB support. | Supports EJBs, JMS, and cross-module dependencies; promotes loose coupling. |
Key Differences Summary
- Modularity: WAR is monolithic for web layers; EAR enables composition of multiple WARs/JARs.
- Server Requirements: WAR works on lightweight web servers; EAR needs a full JEE server.
- Evolution: With microservices and cloud-native trends (e.g., Spring Boot, Quarkus), WARs are often used for containerized deployments (Docker), while EARs are less common but still vital for legacy enterprise apps.
For hands-on examples, refer to official Jakarta EE docs: Jakarta EE Tutorial or Oracle’s Java EE archives: Java EE Packaging.