jar vs war in Spring Boot

June 25, 2021 Ravi Yasas

Use jar not war

If you run mvn clean install in Spring Boot, you will get a fat jar file.
It contains everything like dependencies, embedded web server... etc.
You can just run java -jar jarFile in a JVM, the default is Tomcat embedded server or you can use Jetty.
You don't need any web server or application server to run spring boot jars.
Because spring boot will provide us a production-ready jar file with the embedded tomcat.
If you need to run spring boot applications in existing web servers, you may have to create war instead of a jar.
Spring Boot supports only Tomcat, Jetty, and Undertow as the embedded server