Spark Framework (Java)

Spark Framework (not to be confused with Apache Spark, the big data engine) is a fiercely minimalist, incredibly lightweight, and highly popular "Micro-Framework" for Java. While Spring Boot and Java EE are massive, heavy-duty engines designed for massive corporate architectures, Spark was explicitly designed for speed, simplicity, and rapid prototyping. It is heavily inspired by Ruby's Sinatra framework. The absolute core superpower of Spark is its "Expressive, Zero-Boilerplate Routing." A developer can literally write a fully functioning web server in a single file with exactly three lines of code. There are no massive XML configurations, no complex annotations, and no heavy dependency injection engines to fight with. You just define a route (`get("/hello", (req, res) -> "Hello World");`) and hit run. Because it completely strips away the terrifying complexity of traditional Java web development, it is massively popular among students, hackathon developers, and engineers needing to quickly spin up a tiny, functional REST API without the bloat of Spring.