I had a friend who said:
Docker is amazing. You can use it to replicate production and all its quirks on your local machine. Then you can deploy that instance straight through all the staging workflows super-quick.
Now this would be true if the developers were writing Ruby, PHP or Go – where there was a direction binary link to the operating system.
But when using Java – there is already a virtual layer between the operating system and the language, making consistency of operation regardless of the underlying operating system.
Arguably, in this case, the benefits of running Docker for developers locally to replicate the production environment are negated. (Compared to Ruby, PHP or Go).
I'm open to discussion on this and am keen to hear a dissenting point of view (with evidence).
Are the development benefits of using Docker negated when using Java compared to other languages closer to Unix binaries?
Best Answer
Not at all.
Imagine you're running the version 1.8.0 of Java on both your development machine and the server. By the way, you're working simultaneously on two projects, both using Java.
One day, a bug is found in JVM, and the servers which run the first project you're working on are migrated to 1.8.1. By the way, the servers running the second project aren't affected by the bug, and are managed by a different team of system administrators, who may not be willing to update to 1.8.1.
Now, at least for one of the projects, you're running a different version of Java.
This may not bother you too much (until one server migrates to 1.9, while the other one keeps the old version), but this would mean that you're not replicating production environment any longer on your local machine, which makes it possible for tiny bugs to creep in.
If you imagine that your file system, your dependencies, your security settings, your local configuration and your version of Linux itself differ from production, you are putting yourself at risk of writing code which will fail in production. Instead of taking this risk, you could be using virtualization or Docker, with minor to no productivity loss.