Event publishing with ApplicationEventPublisher in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to inject ApplicationEventPublisher in a Spring component.

Spring Boot

public class MyComponent {

    private final ApplicationEventPublisher [1];

    public MyComponent(ApplicationEventPublisher publisher) {
        this.publisher = publisher;
    }
}

Drag options to blanks, or click blank then click option'

AeventPub

Bpublisher

CeventPublisher

DapplicationEventPublisher

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name that does not match the constructor parameter.

Using a very long or unclear variable name.

The variable name for ApplicationEventPublisher is commonly publisher to keep code clear and simple.

2fill in blank

medium

Complete the code to publish a custom event using ApplicationEventPublisher.

Spring Boot

public void publishEvent(String message) {
    MyCustomEvent event = new MyCustomEvent(this, message);
    [1].publishEvent(event);
}

Drag options to blanks, or click blank then click option'

AeventPublisher

BapplicationEventPublisher

Cpublisher

DeventPub

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name that was not declared.

Calling a wrong method instead of publishEvent.

The publisher variable is used to call publishEvent method to send the event.

3fill in blank

hard

Fix the error in the event class constructor to properly extend ApplicationEvent.

Spring Boot

public class MyCustomEvent extends ApplicationEvent {

    private final String message;

    public MyCustomEvent([1] source, String message) {
        super(source);
        this.message = message;
    }

    public String getMessage() {
        return message;
    }
}

Drag options to blanks, or click blank then click option'

AObject

BString

CApplicationEvent

DMyCustomEvent

Attempts:

3 left

💡 Hint

Common Mistakes

Using String or other types instead of Object for source.

Not calling super(source) in constructor.

The constructor must accept an Object as the source parameter to pass to the superclass ApplicationEvent.

4fill in blank

hard

Fill both blanks to create and publish a new event with a message.

Spring Boot

public void sendMessage(String msg) {
    [1] event = new MyCustomEvent(this, msg);
    [2].publishEvent(event);
}

Drag options to blanks, or click blank then click option'

AMyCustomEvent

Bpublisher

Cevent

DApplicationEventPublisher

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong class name for the event.

Trying to call publishEvent on the event object instead of the publisher.

First, create an instance of MyCustomEvent. Then use the publisher variable to publish it.

5fill in blank

hard

Fill all three blanks to define a Spring component that publishes an event with a message.

Spring Boot

@Component
public class EventPublisher {

    private final [1] publisher;

    public EventPublisher([2]) {
        this.publisher = eventPublisher;
    }

    public void publish(String msg) {
        [3] event = new MyCustomEvent(this, msg);
        publisher.publishEvent(event);
    }
}

Drag options to blanks, or click blank then click option'

AApplicationEventPublisher publisher

BApplicationEventPublisher

CMyCustomEvent

DApplicationEventPublisher eventPublisher

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up field declaration and constructor parameter syntax.

Using wrong class names or missing variable names.

The field is declared as ApplicationEventPublisher. The constructor parameter is named eventPublisher of type ApplicationEventPublisher. The event variable is of type MyCustomEvent.