Clojure

Clojure is a dynamic, functional programming language and a modern dialect of Lisp. Rich Hickey designed it and released the first version in 2007. It runs on the Java Virtual Machine, giving it access to the full Java ecosystem while offering a fundamentally different programming model — immutable persistent data structures, first-class functions, and a macro system for code generation at compile time.

The current stable release is Clojure 1.12. The language treats concurrency as a core concern: its immutable-by-default approach eliminates many categories of race conditions, and built-in constructs like atoms, refs, and agents provide managed mutable state when needed. ClojureScript compiles Clojure to JavaScript, extending the language to browser and Node.js environments. REPL-driven development is central to the Clojure workflow — developers interact with a running program rather than following an edit-compile-run cycle.

The reference documentation covers the language, standard library, and tooling. The source code is available on GitHub under the Eclipse Public License.