Where Are the Logs for a Thread

Lucee 6.0 has optional debugging for threads, but it’s not quite available in beta just yet

https://luceeserver.atlassian.net/browse/LDEV-3380

in 5.3 what you can do is the following

var debugData = getPageContext().getDebugger().getDebuggingData(getPageContext());
FileWrite('c:\temp\log-#gettickCount()#.json',serializeJson(debugData));