@Retention(value=RUNTIME)
 @Target(value=METHOD)
public @interface OnOpen

This method level annotation can be used to decorate a Java method that wishes to be called when a new web socket session is open.

The method may only take the following parameters:-

• optional Session parameter
• optional EndpointConfig parameter
• Zero to n String parameters annotated with the jakarta.websocket.server.PathParam annotation.

The parameters may appear in any order.