Make FieldSet non-final [BATCH-283] #3296
I think we can probably allow extensions to FieldSet. It's a tough call when writing frameworks, how much to expose for extension, and traditionally Spring has been rather lax. In this case I can see that it is a pretty useful extension point, and the package is definitely not internal, since it necessarily contains the FieldSetMapper interface. I will change FieldSet to be non-final.
Referenced from: commits 8afab08