I was using this code block. But the getSessionAttributes() was showing error. I used library "spring-messaging.jar-4.0.0 Release". I found on their website that this function exists in this class. But the library I've used doesn't contain this class. How can this be solved? I cannot update the class file and add the function!

@MessageMapping("/chat.addUser")
@SendTo("/topic/public")
public ChatMessage addUser(@Payload ChatMessage chatMessage,
                           SimpMessageHeaderAccessor headerAccessor) {
    // Add username in web socket session
    headerAccessor.getSessionAttributes().put("username", chatMessage.getSender());
    return chatMessage;
}