Scheduled websocket push with Springboot

Before starting, make sure that you have the websocket dependencies in your pom.xml. For instance, the most important one:

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-websocket</artifactId>
    <version>${org.springframework-version}</version>
</dependency>

Then, you need to have your configuration in place. I suggest you start with simple broker.

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {

    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        registry.addEndpoint("/portfolio").withSockJS();
    }

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

}

Then your controller should look like this. When your AngularJs app opens a connection on /portfolio and sends a subscription to channel /topic/greeting, you will reach the controller and respond to all subscribed users.

@Controller
public class GreetingController {
    
    @MessageMapping("/greeting")
    public String handle(String greeting) {
        return "[" + getTimestamp() + ": " + greeting;
    }
}

With regard to your scheduler question, you need to enable it via configuration:

@Configuration
@EnableScheduling
public class SchedulerConfig{}

And then schedule it:

@Component
public class ScheduledUpdatesOnTopic{

    @Autowired
    private SimpMessagingTemplate template;
    @Autowired
    private final MessagesSupplier messagesSupplier;

    @Scheduled(fixedDelay=300)
    public void publishUpdates(){
        template.convertAndSend("/topic/greetings", messagesSupplier.get());
    }
}

Hope this somehow clarified the concept and steps to be taken to make things work for you.