Key Components of a Netty Application

Netty is a non‑blocking, event‑driven network programming framework. A Netty application is typically started with a Bootstrap (or ServerBootstrap) which configures the program and links the various components.

EventLoop : Handles I/O operations for a Channel; a single EventLoop can serve multiple Channels.

EventLoopGroup : A collection of EventLoops.

ChannelPipeline : The mechanism that chains handlers; it relies on EventLoop and EventLoopGroup because all three are related to event processing.

Channel : Represents a socket connection or other I/O entity and works with an EventLoop to perform I/O.

Future / ChannelFuture : All I/O operations are asynchronous; they return a ChannelFuture that can be awaited or have a listener registered to be notified of success or failure.

ChannelInitializer : Configures handlers by providing a ChannelPipeline and adding handlers to it. The last handler added cannot be a ChannelOutboundHandler; inbound handlers are executed in order for outbound data, while outbound handlers run in reverse order for inbound data.

ChannelHandler : Supports various protocols and data processing. The most common are ChannelInboundHandler for handling received data (where business logic is usually placed) and ChannelOutboundHandler for handling data being sent.