We noticed our server startup became very slow when we setup our Agent. Investigating further we notice that LoadCache.lookupClass is called for the class "com.sun.xml.internal.bind.v2.runtime.unmarshaller.Receiver" (which is in boot classpath) with the Tomcat Application Classloader as the parameter. However, unlike other classes, this method is called with the same loader thousands of times for this class.

Looking at the LoadCache code: https://git.io/vxPJD it appears that if lookupClass is looking for a boot class in boot classloader it would work (cache the class in bootMap). However, if it searches for boot class in the hierarchy of application classloader, then in infact does not cache the boot class, which results in the search executing again and