Spring Boot applications are slightly different from tradition Java web applications (or Jakarta EE applications) in that, by default, they create a
JAR file with an embedded server, rather than a traditional
WAR file that’s deployed on a standalone Servlet container or fully featured Java EE server.
Alternatively, Spring Boot applications can be packaged as
WAR files, too.
Follow the instructions in Spring Boot documentation on how to do this.
The main differences between
WAR packaging are as follows:
there is no need for a server binary install; a Java runtime is all that’s needed
bigger package size
a separate Java Servlet container is needed
you have a free choice of servers, including Jetty, Tomcat, WildFly, GlassFish, and others
smaller package size
See Using Spring Boot Properties for additional details.
You can read more about Spring applications and how to deploy them at the official Spring website.