I live in Java world and docker solves exactly 0 problems for me.
Maven or Gradle deals with assembling all the necessary jars into a single directory (or uberjar if you want, I don't like it).
JVM is another directory.
Running application is a shell script of 2-3 lines.
So my Java application is: directory with JVM, directory with jars and start.sh.
It works almost everywhere. It's simpler than docker. I can replace JVM with windows version and start.sh with start.bat and it'll run on Windows. Natively. Can't do that with Docker.
To build my application one would need to have maven (one directory), JVM (another directory) and project sources. Set up two env vars (JAVA_HOME, PATH) and run mvn verify. That's about it. Windows, Linux, macOS, doesn't matter.
Single binary is simpler than a directory with some files. But not much simpler.
I use docker, because that's the way things are done nowadays. I think that for personal project which does not need Kubernetes, I wouldn't use it.
I totally agree with and think we've all accepted it's (docker/oci's) place regarding deployability on infrastructure not managed by java developers.
Recently I've done a few migration projects and the biggest pain-point (not really a pain but not k8 friendly) is the containerization of JEE servers/services. As these solved most of what containers provide (deployment wise) albeit only for java. 'DevOps' generally killed this (and the related tech debt) but it's hard to validate the utility of any of this as the 'generalized' solution feels like it's compromised down to a point of convenience.
In saying that I do enjoy having a deployment platform that is always going to be Linux(like).
I don't think I would use it either for a personal project; but I would perhaps investigate how hard it would be to add some level of "kublet" (cri) like jvm integration
Maven or Gradle deals with assembling all the necessary jars into a single directory (or uberjar if you want, I don't like it).
JVM is another directory.
Running application is a shell script of 2-3 lines.
So my Java application is: directory with JVM, directory with jars and start.sh.
It works almost everywhere. It's simpler than docker. I can replace JVM with windows version and start.sh with start.bat and it'll run on Windows. Natively. Can't do that with Docker.
To build my application one would need to have maven (one directory), JVM (another directory) and project sources. Set up two env vars (JAVA_HOME, PATH) and run mvn verify. That's about it. Windows, Linux, macOS, doesn't matter.
Single binary is simpler than a directory with some files. But not much simpler.
I use docker, because that's the way things are done nowadays. I think that for personal project which does not need Kubernetes, I wouldn't use it.