Anonymous access spamming INFO messages in the logs

Every time an anonymous user enters the instance (if allowed at Global Permissions), the logs print:

2017-08-03 17:43:03,205 INFO [read-only-transaction:thread-1] [atlassian.confluence.user.DefaultUserAccessor] getUserNamesWithConfluenceAccess Found USE permission with no associated username or group: [USECONFLUENCE,0,null,null,null]

In large public-facing instances, it can easily flood the logs.

Since Confluence expects such NULL values in the database to allow anonymous access, we could have, at least, clearer logs indicating what is actually happening.

In order to suppress the logs:

1. Go to General Configuration > Logging and Profiling;
2. In the "Class/Package Name" field, put the class

   com.atlassian.confluence.user.DefaultUserAccessor

3. Change New Level to WARN;
4. Click Add entry