Attaching jart7.zip project showing the issue(s).
First src/main/webapp looks mandatory,
Then ServletContainerInitializer are ignored,
Finally META-INF/resources are ignored.
If the packaging type if jar replacing src/main/webapp by src/main/resources/META-INF/resources would help and using target/classes as WEB-INF/classes would solve everything. An alternative would be to use the package jar and add it in the WebappClassLoader. The first one is better since it allows hot redeployment of resources