Q:

What does this websocket api means?

I have created spring boot websocket project. I want to know what does 

localhost:9090/gs-guide-websocket/parm1/param2/websocket

This Api means? 
here i know 'gs-guide-websocket' is my websocket end point but what is the rest of all?
WebSocketConfig.java
@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {

@Override
public void configureMessageBroker(MessageBrokerRegistry config) {
    config.enableSimpleBroker("/topic");
    config.setApplicationDestinationPrefixes("/app");
}

@Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
    registry.addEndpoint("/gs-guide-websocket").withSockJS();
}

Controller.java
@MessageMapping("/hello")
@SendTo("/topic/greetings")
public Greeting greeting(HelloMessage message) throws Exception {
    Thread.sleep(1000); // simulated delay
    return new Greeting("Hello, " + HtmlUtils.htmlEscape(message.getName()) + "!");
}

In the about Url what is the sender identity and whom we are sending?
Code is working fine.

A:

The @MessageMapping annotation ensures that if a message is sent to destination "/hello", then the greeting() method is called.
After the 1 second delay, the greeting() method creates a Greeting object and returns it. The return value is broadcast to all subscribers to "/topic/greetings" as specified in the @SendTo annotation.
Refer This Example

