I have a Java JSF2 web based application deployed on a Tomcat server, and since we moved to Java 8 / Tomcat 8 this error appears a lot in the tomcat output:
I was presenting the same problem
Today I updated my pom.xml file to jsf version: 2.2.15 and that ERROR log was gone.
com.sun.faces jsf-api ${jsf.version} provided com.sun.faces jsf-impl ${jsf.version} provided