Serious question: when should one use Java for greenfield projects in 2026?

Java & Spring is a good choice whenever you want your application to work and be maintainable 10 years from now, without having to replace the framework and half of the libraries you used. I see few good reasons to ever use something with unstable ecosystem (like Javascript with NodeJS) over Java these days.

When building boring web applications with a sizeable team that need to run for a long time. Hiring developers is easy since there are many, there is nearly no magic and the language is quite strict and type safe so it works well with a large team.

And that "team" nowadays may also consist of many AI agents. In my experience Claude Code for example works very well with a typed, slightly boring language with lots of framework and library support. Because it doesn't compile when you get something wrong, instead of getting a vague runtime issue that Claude can't always see.

Not at all a bad choice.

It's stable to the point of boring, and there's no shortage of people who know the language and can work with it, it's got best in class tooling, decades worth of libraries almost all very mature. Most of the language's issues are from legacy code bases coded in a style that isn't really relevant to a greenfield project.

I wrote about it 13 years ago, some of it still stands true. https://news.ycombinator.com/item?id=5857495

When you are already familiar with it or work in a Java shop, there are better options if you are starting from scratch, but if you already have 50 guys that know Java it's a pretty big ask for all of them to switch.

When you work at a Java shop. Kotlin is much nicer if you have to run on the JVM but aren't restricted to Java.

Same question for .net or C#

Why should anyone use it over Java? Ms is hostile towards its developers, it creates new versions of things, deprecates previous versions, uses confusing naming for newer versions.. etc.

java is a great language for server side projects. it is actively maintained, the biggest issues with it have JEPs, and it’s very friendly to AI authors

When you think a garbage collected language is a good fit for whatever you're building?

Jruby is nice - runs Ruby on a Java Virtual Machine with full concurrency and Ahead Of Time compilation

Whoever works with, or chooses Java, is not doing it for the language itself, be it beautiful or not. Java has a huge ecosystem, from battle tested integrations to optimized images to build pipelines to whatever, so at the same you're buying access to all this world (yes, more than an environment). And of course transferable skills. I'm not saying Java is alone offering this, also not saying every feature is the best, but you can have them all, and even choose from different options.