It's only enabled by default in FIR and might be turned on with a CLI flag
The main idea is that default FarFS re-read ZIP file list each time when
class file is requested that is quite slow.
We read it once and them reading bytes from the known offset.
Also, unlike the default version we don't perform attributes check on each access
On the one hand, it works faster on the other it might not notice that one
of the JAR has been changed during compilation process
But looks like it's not supposed to be a frequent even during
compilation of a single module
Denis.Zharkov
8f06e59d3b