Office Connector logging is no longer working

Since version 3.4.3 of the Office Connector, logging for the plugin is no longer working.

Steps to Reproduce

1. Start up a version of Confluence that bundles OfficeConnector 3.4.3 or above (5.9.x), or install this version into Confluence 5.8.x
2. Set debug logging on these two classes:
   • com.benryan
   • com.atlassian.confluence.extra.officeconnector
3. Upload an excel, word and ppt document and wait for the indexing to kick off (~1 minute)
4. You should see DEBUG lines in the atlassian-confluence.log, however there is none. There is no logging at other levels either.

I suspect this began after implementing the Office Connector canary process, however it could also have been due to the dependency changes required for plugins4.

Logging for the canary process and some parts of the Office Connector  (eg below) go to the catalina.out, but is not formatted in the usual way (eg the timestamp). This is because it uses an SLF4J SimpleLogger, which is by design - it runs in an entirely separate JVM and is stripped down to pure essentials. It appears as though the dependencies from this module are bleeding into the main JVM and breaking logging for the whole plugin.

147073 [scheduler_Worker-10] INFO com.atlassian.confluence.extra.officeconnector.index.excel.ExcelXMLTextExtractor - Not enough memory to extract all text from 'test.xlsx'. The attachment will be partially searchable.