Spring Boot simplifies deployment compared to traditional Spring by embedding the application server inside the app itself, collapsing what used to be a multi-step server-and-WAR setup into a single runnable JAR.
Key Points: • Traditional Spring apps are packaged as WAR files and require a separately installed and configured application server like Tomcat. • Spring Boot embeds Tomcat, Jetty, or Undertow directly, so the JAR is fully self-contained. • Running the app is as simple as java -jar app.jar, with no external server installation or configuration step. • This self-contained model maps naturally onto containers, since a Dockerfile just needs the JAR and a JVM base image. • Auto-configuration further reduces the amount of manual server/framework wiring needed before the app can run.
Example: Where a traditional Spring app might need a DevOps engineer to install and configure Tomcat on a server before deployment, a Spring Boot app can be deployed by simply copying the JAR and running java -jar, or by shipping a Docker image built directly from it.
Interview Tip: A concise interview answer is:
"Traditional Spring apps need a separately managed application server and WAR packaging. Spring Boot embeds the server into the JAR itself, so deployment is just java -jar, with no external server setup required. That also makes it a much more natural fit for containerized deployments."