Why should I use JSON.stringify() inside the STOMP send() method? - spring

Question

I'm trying to figure out how to write a simple chat on spring and Websocket.
I have simple configuration class :
#Configuration
#EnableWebSocketMessageBroker
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
#Override
public void configureMessageBroker(MessageBrokerRegistry config) {
config.enableSimpleBroker("/topic");
config.setApplicationDestinationPrefixes("/app");
}
#Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/hello").withSockJS();
}
}
and class controller ike this :
#Controller
public class GreetingController {
#MessageMapping("/hello")
#SendTo("/topic/greetings")
public Greeting greeting(HelloMessage message) throws Exception {
Thread.sleep(3000); // simulated delay
return new Greeting("Hello, " + message.getName() + "!");
}
}
I understand that he gets requests via app/hello, but I don't understand why i have to use JSON.stringify({ 'name': name })call inside a js script?:
...
function sendName() {
var name = document.getElementById('name').value;
stompClient.send("/app/hello", {}, JSON.stringify({ 'name': name }));
}
...
That is, this function creates json and passes it to a function that performs deserialization, as I understand it, but can we do without it? or is it an obligatory condition?
Greeting class:
public class Greeting {
private String content;
public Greeting(String content) {
this.content = content;
}
public String getContent() {
return content;
}
}
HelloMessage class:
public class HelloMessage {
private String name;
public String getName() {
return name;
}
}