Just to notice,
As stated in Spring Documentation about TomcatInstrumentableClassLoader, spring-instrument-tomcat.jar can only be used with Tomcat 6 or Tomcat 7.
From Tomcat 8, one’s got to use Tomcat’s own
NOTE: Requires Apache Tomcat version 6.0 or higher, as of Spring 4.0. This class is not intended to work on Tomcat 8.0+; please rely on Tomcat’s own InstrumentableClassLoader facility instead, as autodetected by Spring’s TomcatLoadTimeWeaver.