Why use Node.js vs Java?

Node.js is widely used across I/O-intensive real-time application domains since it uses a non-blocking, event-driven I/O model that shares JavaScript between the client and server to achieve fast development. It is scalable and works well in lightweight applications requiring numerous concurrent connections. At the same time, Java fits large enterprise applications, where all type-checking is more intensive and multi-threading is more high-level. It depends on the requirements of the project.