I am working on a chat application using springboot (WebSocket) in the backend.
I followed a youtube video of how to create one , and It’s the same code the youtuber showed. However, when I run the application an error arise because of Lombok. That was surprising since I used Lombok in other projects and it works fine.

WebSocketEventListner class:

@Component
@RequiredArgsConstructor
@Slf4j
public class WebSocketEventListener {

    private final SimpMessageSendingOperations messagingTemplate;

    @EventListener
    public void handleWebSocketConnectListener(SessionDisconnectEvent event) {

        StompHeaderAccessor headerAccessor = StompHeaderAccessor.wrap(event.getMessage());
        String username = (String) headerAccessor.getSessionAttributes().get("username");

        if (username != null) {
            log.info("User disconnected: {}", username);
            var chatMessage = ChatMessage.builder()
                    .type(MessageType.LEAVE)
                    .sender(username)
                    .build();
            messagingTemplate.convertAndSend("/topic/public", chatMessage);
        }

    }



}

WebSocketConfig class:

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {

    @Override
    public void configureMessageBroker(MessageBrokerRegistry registry) {

        registry.setApplicationDestinationPrefixes("/app");
        registry.enableSimpleBroker("/topic");



    }

    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        registry.addEndpoint("/ws").setAllowedOrigins("*").withSockJS();

    }
}

ChatMessage class:

@Getter
@Setter
@Builder
public class ChatMessage {
    private String content;
    private String sender;
    private MessageType type;
}

ChatController class:

@Controller
public class ChatController {

    @MessageMapping("/chat.sendMessage")
    @SendTo("/topic/public")
    public ChatMessage sendMessage(@Payload ChatMessage chatMessage) {
        return chatMessage;
    }


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

}

pom.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.4.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.prodigy</groupId>
    <artifactId>server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>server</name>
    <description>server</description>
    <url/>
    <licenses>
        <license/>
    </licenses>
    <developers>
        <developer/>
    </developers>
    <scm>
        <connection/>
        <developerConnection/>
        <tag/>
        <url/>
    </scm>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <annotationProcessorPaths>
                        <path>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </path>
                    </annotationProcessorPaths>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

I tried different versions of Lombok and nothing worked.
I rebuilt the project with different java version and didn’t work.
I enabled the annotation processing in IntelliJ.