The Serverless framework ‘serverless deploy’ deploys whatever .jar you have packaged and ready to go within your source project.
If you make local code changes but don’t re-build your .jar, serverless thinks you don’t have any changes to deploy:
$ serverless deploy ... Serverless: Packaging service... Serverless: Service files not changed. Skipping deployment...
If you’re building a maven-based project, ‘mvn clean package’ first, then run your ‘serverless deploy’.