Solon Framework Uses Listener Interface Instead of Annotations for WebSocket Endpoints

The Solon Java framework takes a different approach to WebSocket development by replacing the standard JSR-356 lifecycle annotations — such as @OnOpen, @OnMessage, and @OnClose — with a WebSocketListener interface. Developers retain the @ServerEndpoint annotation for path declaration but handle lifecycle events by extending SimpleWebSocketListener or implementing WebSocketListener directly. Solon supports two deployment configurations: a shared-port mode where HTTP and WebSocket traffic use the same port, and an independent-port mode where WebSocket runs on a dedicated port configurable via app.yml. Path variables and query parameters are both accessed through a unified socket.param() method, simplifying endpoint logic. The framework's IoC container auto-discovers endpoint classes, requiring only a single enableWebSocket(true) call in the application's main method.