Q: Font-cache refresh warning?

Hi,

One for Adrian, I presume: after updating my local sandbox, I got  
warnings about the FontCache being refreshed.
At first, I thought this was due to the updates, but they re-occur  
every run.

     [junit] WARNING: I/O exception while reading font cache  
(org.apache.fop.fonts.FontCache; local class incompatible: stream  
classdesc serialVersionUID = 605232520271754718, local class  
serialVersionUID = 60523252027175471). Discarding font cache file.

Any idea where these come from?
Does anyone else notice this too, or should I go looking elsewhere?
Is this something to worry about?


Cheers


Andreas