In an entity implementation, one can override getEntityTypeName() - or 
call getMutableEntityType().setName() - so it's not necessarily a 
classname. That's just the default.

Changing makeValidFilename to not use spaces sounds sensible. After all, 
you can have other characters in a filename if you're willing to escape 
them!

Currently it removes those chars rather than replacing with "_" but I 
think either would be fine