javnim

Javnim is a statically-typed programming language and compiler that targets the Java Virtual Machine (JVM). It combines Nim-inspired syntax and language features with Java interoperability to provide concise, high-performance applications on the JVM.

Developed as an open-source project in the early 2020s by contributors from the Nim and Java communities, Javnim aims to offer a language with the readability of Nim and the broad ecosystem of Java by compiling to JVM bytecode and integrating with existing Java libraries and frameworks.

Javnim emphasizes compile-time metaprogramming and type inference, while preserving explicit control when needed. It supports Nim-like macros or templates, optional type inference, and a robust macro system for code generation. It runs on the JVM's garbage-collected heap, leveraging the JVM's performance characteristics. It provides seamless interop with Java classes, annotations, and the standard libraries, enabling direct use of Java or Kotlin code; packages can be distributed as Java-compatible jars. Concurrency is supported via asynchronous constructs and futures; memory safety features and compile-time checks help catch errors early.

The syntax borrows Nim's indentation-based blocks and concise syntax, combined with explicit exports for Java interop. The language compiles to Java bytecode and can call Java methods directly; it also supports annotation-driven interop.

The reference compiler, javnimc, translates Javnim source to JVM bytecode; the toolchain integrates with existing JVM build systems such as Maven and Gradle, and supports package management through a central repository.

Target applications include backend services, data processing, and performance-sensitive components that benefit from Nim-like expressiveness while requiring access to Java libraries. Community use is growing but the ecosystem remains smaller than that of Java, with ongoing work to improve documentation and interop reliability.