Configure embedded Jetty server in spring boot

Spring boot use tomcat as default embedded tomcat server to run a web application but you can configure jetty server to replace tomcat in easy steps.

Add spring-boot-starter-jetty dependency

We need to do two things here:-

1. Exclude default dependency spring-boot-starter-tomcat added in spring-boot-start-web
2. Add spring-boot-starter-jetty dependency.

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jetty</artifactId>
</dependency>

That’s it. You have replaced tomcat with jetty server.

Observations

When you build spring boot maven project, it smartly replace tomcat jars with jetty dependency jars from maven dependency as follows:

▼ Maven Dependencies
  ► tomcat-embed-core-x.y.z.jar
  ► tomcat-embed-el-x.y.z.jar
  ► tomcat-embed-websocket-x.y.z.jar
  ► jetty.servlets-x.y.z.jar
  ► jetty.continuation-x.y.z.jar
  ► jetty-http-x.y.z.jar
  ► jetty-webapp-x.y.z.jar
  ► jetty-servlet-x.y.z.jar
  ► jetty-security-x.y.z.jar
  ► jetty-server-x.y.z.jar

When you start spring boot application, You will in the logs that jetty is serving your web application now:-

2020-04-25 13:25:02.208 - INFO [main] c.a.s.SpringbootApplication              :  Starting SpringbootMicroserviceApplication on Ashishs-MBP with PID 2910
2020-04-25 13:25:02.213 - INFO [main] c.a.s.SpringbootApplication              :  No active profile set, falling back to default profiles: default
2020-04-25 13:25:03.317 - INFO [main] o.s.b.w.e.j.JettyServletWebServerFactory :  Server initialized with port: 8080
2020-04-25 13:25:03.320 - INFO [main] org.eclipse.jetty.server.Server          :  jetty-9.4.27.v20200227; built: 2020-02-27T18:37:21.340Z; git: a304fd9f351f337e7c0e2a7c28878dd536149c6c; jvm 1.8.0_211-b12
2020-04-25 13:25:03.350 - INFO [main] o.e.j.s.h.ContextHandler.application     :  Initializing Spring embedded WebApplicationContext
2020-04-25 13:25:03.476 - INFO [main] o.e.jetty.server.handler.ContextHandler  :  Started o.s.b.w.e.j.JettyEmbeddedWebAppContext@30c3ae63
2020-04-25 13:25:03.476 - INFO [main] org.eclipse.jetty.server.Server          :  Started @2273ms