4.0.0 org.springframework.boot spring-boot-samples ${revision} spring-boot-sample-websocket-undertow Spring Boot WebSocket Undertow Sample Spring Boot WebSocket Undertow Sample ${basedir}/../.. org.springframework.boot spring-boot-starter-websocket org.springframework.boot spring-boot-starter-tomcat org.springframework.boot spring-boot-starter-undertow org.springframework.boot spring-boot-starter-test test org.springframework.boot spring-boot-maven-plugin