Spring Boot deployment on WLP (WebSphere Liberty) throws CWWKC0044W error

Spring Boot deployment on WLP (WebSphere Liberty) throws CWWKC0044W error

You need to be include the Liberty spring boot starter, and exclude the Tomcat starter (since youre using Liberty instead of Tomcat).

Your dependencies should look something like this:

dependencies {
  ...
  // Include liberty and exclude tomcat
  compile(io.openliberty.boot:liberty-spring-boot-starter:0.5.0.M1)
  compile(org.springframework.boot:spring-boot-starter-web) {
    exclude module: spring-boot-starter-tomcat
  }
  ...
}

For a more detailed walkthrough of a basic HelloServlet with Liberty+Spring, check out Tom Watsons blog post: Open Liberty Spring Boot Starter

I was able to get rid of the error by exclusion of the Log4j transitive dependency. It was necessary to remove it from every spring-boot-starter-* dependency (web and thymeleaf in my case). Therefore, Ive excluded it on the global level:

configurations {
    implementation {
        exclude group: org.apache.logging.log4j
    }
}

Im using Gradle 4, so the configuration is implementation. It should be compile for older versions.

However, I still dont know what was the root cause, so some explanation would be nice. I suspect some older/incompatible versions of Java.

Spring Boot deployment on WLP (WebSphere Liberty) throws CWWKC0044W error