When installing or loading Monitoring Service, MUC Service or User Service (two latter being deprecated) plugins it shows in console:
Kov 24, 2018 10:45:03 AM com.sun.jersey.api.core.PackagesResourceConfig init
INFO: Scanning for root resource and provider classes in the packages:
Kov 24, 2018 10:45:03 AM com.sun.jersey.server.impl.application.WebApplicationImpl _initiate
INFO: Initiating Jersey application, version 'Jersey: 1.19.4 05/24/2017 03:46 PM'
Successfully loaded plugin 'monitoring'.
Although it is an INFO type of message, it is shown in red color and it looks more like an error than an informative message.