JDA is a mature Java library for building Discord bots. It implements both the Discord REST API and the real-time WebSocket gateway, exposing them through a clean event-driven API. Developers configure a JDA instance via JDABuilder or DefaultShardManagerBuilder, register typed event listeners, and make HTTP calls through fluent RestAction objects. Internally, gateway dispatch handlers parse JSON or ETF payloads, maintain threaded cache views of Discord entities, and translate them into public events, while REST actions are executed through an OkHttp-backed requester with rate-limit handling and retry logic. The library is strictly split into a public API package (net.dv8tion.jda.api) and an internal implementation package (net.dv8tion.jda.internal), so most users depend only on the stable API surface.