caching the value of isTraceEnabled does not allow for complete dynamic control of the logging level. This has ramifications in support scenarios where diagnostics are needed and the ability to reload an instance to enable TRACE level logging is prohibitive.

see examples of TRACE being cached:
grep 'log.isTraceEnabled();' -r * --include='*.java'

Replacement of all if (trace) with calls to log.tracef would be needed.

Note, that some "if (trace)" would have to be replaced by if (log.isTraceEnabled()) calls, as they guard multiple lines of code, and even synchronization blocks