Cannot locate webjars with SpringBoot application running on WebSphere

Question

I have been trying to host Spring Boot application on WebSphere server.

Versions :

• SpringBoot 2.1.6.RELEASE
• WebSphere Liberty 19.0.0.6 with JavaEE 8
• webjars-locator 0.36

The app was successfuly deployed on standalone Tomcat 9.0.22 and webjars could be resolved there. However for WebSphere I receive an error when trying to access webjars from html page :

2019-08-05 10:43:11.839 DEBUG 1 --- [ecutor-thread-6] o.s.web.servlet.DispatcherServlet        : GET "/appcontext/webjars/jquery/jquery.min.js", parameters={}
2019-08-05 10:43:11.845 DEBUG 1 --- [ecutor-thread-6] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to ResourceHttpRequestHandler ["classpath:/META-INF/resources/webjars/"]
2019-08-05 10:43:11.849 DEBUG 1 --- [ecutor-thread-6] o.s.w.s.r.ResourceHttpRequestHandler     : Resource not found
2019-08-05 10:43:11.849 DEBUG 1 --- [ecutor-thread-6] o.s.web.servlet.DispatcherServlet        : Completed 404 NOT_FOUND

And the webjars pattern was successfuly mapped by Spring :

2019-08-05 10:43:09.039 DEBUG 1 --- [ecutor-thread-6] o.s.w.s.handler.SimpleUrlHandlerMapping  : Patterns [/webjars/**, /**] in 'resourceHandlerMapping'

Answer 1

The solution for this is to add classloading entry, with useJarUrls attribute set to true, to WebSphere server.xml file :

<server description="myServer">
    <featureManager>
        <feature>servlet-3.0</feature>
    </featureManager>
    <classloading useJarUrls="true"/> <!-- this line was added -->
    <httpEndpoint httpPort="9080" httpsPort="9443" host="*" id="defaultHttpEndpoint"/>
</server>

This IBM support issue was particulary helpful in solving this problem.