Spring Boot JAR vs WAR Deployment

When deploying a Spring Boot application, you have two main options: deploying as a JAR file with an embedded server or as a WAR file on an external application server. Each approach has its own advantages and trade-offs. Here’s a detailed comparison to help you decide:

1. Spring Boot JAR Deployment

Spring Boot can package your application as a standalone JAR with an embedded server (e.g., Tomcat or Jetty).

Advantages:

• Standalone Deployment: No need for an external application server. Run the app with a single command:

  java -jar your-app.jar

• Simpler Configuration: All configurations are defined within the application, reducing external dependencies.
• Faster Startup: Embedded servers avoid unnecessary components, leading to quicker startups.
• Portable: Easy to deploy across environments (local, staging, production).

Disadvantages:

• Less Control Over the Server: Fine-tuning server behavior can be limited compared to using a full-fledged application server.
• Limited Scalability: Embedded servers are sufficient for small to medium workloads but may not handle large-scale enterprise systems as effectively.

2. WAR Deployment to an Application Server

A WAR file requires an external application server like Apache Tomcat, WildFly, or Payara to deploy.

Advantages:

• Enterprise Features: Application servers offer advanced features like clustering, load balancing, and session replication.
• Standardized Deployment: Aligns with Java EE/Jakarta EE standards, making it compatible with various application servers.
• Centralized Server Management: Ideal for managing multiple applications on a shared server.

Disadvantages:

• Server Management Overhead: Requires installing, configuring, and maintaining the application server.
• More Complex Deployment: Deployment involves copying the WAR file to the server and potentially restarting it.
• Longer Startup Times: Application servers start slower due to their broader functionality.

When to Use Which?

Use JAR Deployment When:	Use WAR Deployment When:
You want a simple, self-contained application.	You already have an existing application server.
Hosting on a VPS or cloud provider (like AWS).	You need advanced server features like clustering.
Microservices architecture or lightweight apps.	You’re deploying to an enterprise-grade setup.
You want faster deployment and less complexity.	Multiple apps share a common application server.

Practical Tips

For Spring Boot JAR:

• Ideal for microservices and modern DevOps workflows (e.g., Docker, Kubernetes).
• Use when hosting on services like AWS, Azure, or simple VPS setups.

For WAR Deployment:

• Best suited for legacy systems or organizations adhering to Java EE standards.
• Choose this for environments where multiple apps share a single application server.

If you’re starting fresh and don’t need a specific application server, JAR deployment with Spring Boot is usually simpler and faster to set up. Let us know your hosting environment, and we can help you decide further!