Porque esse erro?

net.sourceforge.barbecue.BarcodeException: a is not a valid character for Standard 2 of 5 encoding

Whitelabel Error Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue Jun 04 16:41:37 BRT 2019

There was an unexpected error (type=Internal Server Error, status=500).

Error creating barcode.