I’m not sure Tomcat 7 is working on Java9. Also it’s definitely not the version of Java you were using previously as there is really not much chance that XWiki 9.4 was working on Java 9. Even with 11.5 using Java 9 is really not recommended and you should either use Java 11 or go back to Java 8 (which is the safest in general and especially with Tomcat 7).