Library Update for Jar / Programs

I am looking for a library of updates for the software that I am developing. This is a small software, but I would like to fill it with good features. One of them is automatic updating. I developed 2 class libraries to do this work for me, but I need a more robust library because it lacks some features. Between the functions that a library can have, they can be in it:

• Create a differences file based on the old version (e.g. jar). Considering the current version of jar and the new jar file, create a new jar that will be downloaded by customers and place only the files that have changed since the last update.
• Check the checksum. Each file inside the JAR has its own checksum or the entire bank with a checksum.
• Generate this checksum. If possible, when visiting the first subject. File by file or jar by jar, given the new files.
• It would be nice if that makes sense if the input file is a folder or a jar.
• Combine the current can with the loaded one.

PS: I am not writing a web application (which works in a browser).

Thank you for the attention.