Collector makes classs cache from couple of reasons:
1) After application start class browsing is done. After this Collector is instrumenting classes and returning them to application. Caching simplifies this process (if code didn't changed).
2) When you are looking for method during sensor creation, Appmon is collecting those data from collector. This way there is no impact for application itself.
Thx for your reply, so one small remark. Removing the files and restarting the App/JVM would result in in a rebuild of the cache? Why is everybody so afraid about these files?