JARs vs WARs
I think both have their use cases, like a car vs a truck.
Getting started with jar files is definitely easier, it's provided out of the box. However, using war files in a tomcat has a few perks too:
- You can use the "manager" UI to update/redeploy a webapp easely
- You can monitor server status, inspect sessions, basically have a look under the hood
- You can deploy/update multiple wars independently, which might be handy for larger project
...but there is definitely some learning curve to set things up, and it feels a bit ...old. So it's up to you if you want an easy "jar car" or a whole "servlet container truck". ...or you can also have multiple cars. ;) Each has ups and downs.
Pipelines
Like for any other topic, there are very different ways to achieve this. If you use an extern tomcat, you may configure a "script" user and deploy it like this (or similar):
curl -u username:pwd -d path=/something -d war=file:target/someWar.war https://someurl.com/manager/deploy
...or you can go the other way round and create Docker images, or cloud-init VMs or whatever. Or just a shell script to stop it remotely, upload it and start it.
Depending on your situation, the know how of your team mates, etc, one or the other may be easier.