I can't imagine a circumstance where a file with that name would contain valuable data.
But if you are really worried, try using the file
command to attempt to identify the files' types ... based on their contents.
How are they generated?
Well the most likely culprit would be some command that creates or unpacks JAR files. Try correlating the timestamps of the files with what you are / were doing at the time. That would help you narrow it down a bit.