What is jetty?

Jetty is a lightweight, open‑source web server and servlet container written in Java. It can serve static files, run Java web applications, and handle HTTP/HTTPS traffic, all from a small, embeddable library.

Let's break it down

  • Web server: Listens for web requests (like a browser asking for a page) and sends back responses.
  • Servlet container: Executes Java code called servlets that generate dynamic content.
  • Embeddable: You can drop Jetty into any Java program, so it runs inside your application instead of as a separate server.
  • Non‑blocking I/O: Uses modern Java NIO to handle many connections efficiently with fewer threads.

Why does it matter?

Jetty lets developers build and test web services quickly without needing a heavyweight server like Tomcat or WebSphere. Its small size and easy embedding make it ideal for microservices, testing, and IoT devices where resources are limited.

Where is it used?

  • Embedded in popular frameworks such as Eclipse IDE, Apache Hadoop, and Spring Boot.
  • Powers many cloud‑native microservices and APIs.
  • Used in development tools for live reload and hot‑deployment.
  • Runs in routers, gateways, and edge devices that need a tiny HTTP server.

Good things about it

  • Lightweight: Small footprint, fast startup.
  • Embeddable: Simple to add to any Java app.
  • Scalable: Non‑blocking I/O handles many concurrent connections.
  • Flexible: Supports HTTP/2, WebSocket, SPDY, and custom handlers.
  • Active community: Regular updates and good documentation.

Not-so-good things

  • Less feature‑rich than full‑stack servers like Tomcat or JBoss for complex enterprise needs.
  • Configuration can be code‑heavy when embedding, which may be confusing for beginners.
  • Fewer built‑in management tools (e.g., admin consoles) compared to some commercial servers.
  • Performance tuning may require understanding of NIO and thread pools, adding a learning curve.