node-java is a native Node.js addon that provides a bidirectional bridge between Node.js and the Java Virtual Machine (JVM). It allows JavaScript code to instantiate Java classes, call static and instance methods, get/set fields, create arrays, handle Java exceptions, and create dynamic proxies for Java interfaces. The architecture comprises three layers: C++ native bindings (using NAN and JNI), Java helper classes for reflection and method invocation, and a JavaScript API exposed as a single import. The system manages JVM lifecycle, async method dispatch via libuv, and complex type conversions (including primitives, arrays, varargs, and Unicode strings). It is widely used (1890 stars) with active maintenance and cross-platform support (Linux, macOS, Windows, ARM).