Confiusion with .jar file and spring boot

Question

I am a bit confused , why my application is working. I have my spring boot project which compiles into .jar

<groupId>Twitter</groupId>
    <artifactId>twitter-api</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

and the application working fine (it's simple web app). Thing I'm missing here is, why it is working while <packaging> is set to .jar and not .war (as for web app). I mean to use it "normally" I'd put the .war file into webapp folder (talking about tomcat), and then access it xxxx/myapp. But here Im packaging it into .jar and it's working as webapp. Could someone explain me this? Thanks in advance folks!

Answer 1

Tomcat is running inside the JAR. Spring Boot can run as an executable JAR without a Java EE app server or servlet/JSP engine.

Answer 2

Normally Spring Boot embedd a servlet engine into your JAR and start your Application within this embedded servlet engine (Jetty, Tomcat). Have a look at the Spring Boot Project .

This features are called

• Create stand-alone Spring applications
• Embed Tomcat, Jetty or Undertow directly (no need to deploy WAR files)