Jetty vs Netty: What are the differences?

Introduction

Jetty and Netty are two popular open-source Java web servers and frameworks used for building high-performance and scalable web applications. While both are designed for similar purposes, there are several key differences between Jetty and Netty that set them apart.

1. I/O model: One of the key differences between Jetty and Netty lies in their I/O models. Jetty uses a thread-per-request model, where each incoming request is handled by a dedicated thread. This model is suitable for applications that require low latency and a high level of concurrency. On the other hand, Netty utilizes an event-driven and asynchronous I/O model, with a small number of threads handling multiple connections. This model is well-suited for applications with a large number of concurrent connections and high throughput.

2. Protocol support: Jetty and Netty also differ in terms of the protocols they support. Jetty has built-in support for a wide range of protocols, including HTTP, HTTPS, WebSocket, SPDY, and HTTP/2. It provides a comprehensive set of APIs and features for developing web applications. In contrast, Netty is more focused on low-level networking and provides a flexible framework for building custom protocols. While it also supports HTTP and WebSocket, its modular design allows developers to easily extend and customize it for other protocols.

3. Ease of use vs flexibility: Jetty aims to provide a developer-friendly and easy-to-use framework with a rich set of features out-of-the-box. It offers a high-level API and takes care of many low-level details, allowing developers to quickly build web applications with minimal configuration. Netty, on the other hand, prioritizes flexibility and fine-grained control. It provides a low-level API that gives developers more control over the networking and I/O operations. This flexibility comes at the cost of increased complexity and a steeper learning curve.

4. Community and ecosystem: Both Jetty and Netty have active and vibrant communities, with a wide range of libraries, plugins, and tools available for developers. However, Jetty has been around for a longer time and has a larger user base, resulting in a more mature and established ecosystem. This means that there is more documentation, tutorials, and community support available for Jetty. Netty, being newer, may have a slightly smaller ecosystem, but it also has a strong and growing community that continually contributes to its development.

5. Performance: When it comes to performance, both Jetty and Netty are designed to be highly efficient and scalable. However, Netty's event-driven and asynchronous I/O model typically offers better performance and lower resource consumption compared to Jetty's thread-per-request model. Netty's ability to handle a large number of concurrent connections with fewer threads can result in better overall throughput and responsiveness, especially in scenarios with high load or when dealing with long-lived connections.

6. Use cases: Jetty and Netty are well-suited for different use cases. Jetty's ease of use and rich feature set make it a popular choice for building traditional web applications, RESTful APIs, and servlet-based frameworks like Apache Wicket and Spring MVC. It is also widely used in embedded systems and IoT applications. Netty, on the other hand, shines in scenarios that require building custom protocols, high-performance network servers, real-time streaming applications, and distributed systems. Its flexibility and emphasis on low-level networking make it more suitable for these types of use cases.

In summary, Jetty and Netty differ in their I/O models, protocol support, ease of use vs flexibility, community and ecosystem, performance, and use cases. Jetty offers a developer-friendly and feature-rich framework, while Netty provides more flexibility and control, particularly for custom protocols and high-performance networking applications.