JWebAssembly is a Java bytecode to WebAssembly compiler. It uses Java class files as input. That it can compile any language that compile to Java bytecode like Clojure, Groovy, JRuby, Jython, Kotlin and Scala. As output it generates the binary format (.wasm file) or the text format (.wat file). The target is to run Java natively in the browser with WebAssembly.

The difference to similar projects is that not a complete VM with GC and memory management should be ported. It’s more like a 1:1 conversion. The generated WebAssembly code is similar in size to the original Java class files.