Custom Event Cannot be Deserialized

Comienza en BusJacksonAutoConfiguration.java, especialmente en BusJacksonMessageConverter.convertFromInternal en la línea 180, y reproduce el fallo con el TestEvent, @RemoteApplicationEventScan y la configuración de publisher/listener de RabbitMQ que se muestran aquí. Compara la deserialización entre Spring Boot 3.5.7/Spring Cloud 2025.0.0 y las versiones más recientes, y verifica que el RemoteApplicationEvent personalizado se reciba sin el error de null-source.

Describe the bug
After upgrading Spring Boot to 4 and Spring Cloud to 2025.1.0, I am getting similar error in logs as spring-cloud/spring-cloud-bus#284 but in my case for custom events. I can confirm, with Spring Boot 3.5.7 and Spring Cloud 2025.0.0 it works as expected and no error thrown. I am adding samples as below, in my current setup event publisher and listener are different spring boot applications connected to the same RabbitMQ.
P.S: First I bumped versions for the event publisher, and listener was able to receive custom events without any problem. After bumped versions for event listener, it started failing to deserialize.

Sample

Event class definition:

import lombok.EqualsAndHashCode;
import lombok.Getter;
import org.springframework.cloud.bus.event.RemoteApplicationEvent;

@EqualsAndHashCode(callSuper = true)
public class TestEvent extends RemoteApplicationEvent {
  @Getter
  private String key;

  public TestEvent() {
  }

  public TestEvent(Object source, String originService, String destination, String key) {
    super(source, originService, () -> destination);
    this.key = key;
  }
}

Spring boot application entrypoint:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.bus.jackson.RemoteApplicationEventScan;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.mongodb.config.EnableMongoAuditing;
import org.springframework.data.mongodb.repository.config.EnableMongoRepositories;

@SpringBootApplication
@EnableMongoRepositories
@ComponentScan(basePackages = {"org.test"})
@EnableMongoAuditing(auditorAwareRef = "auditorProvider")
@RemoteApplicationEventScan(basePackages = {"org.test"})
@EnableFeignClients
public class TestServiceApplication {
  public static void main(String[] args) {
    SpringApplication.run(TestServiceApplication.class, args);
  }
}

Event listener:

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Component
@Slf4j
public class TestEventListener {
  @EventListener
  public void onTestEvent(TestEvent event) {
    log.info("Received TestEvent {}", event);
  }

Event publisher:

import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.bus.BusProperties;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.stereotype.Service;

@Service
@Slf4j
@RequiredArgsConstructor
public class PublisherService {
  private final ApplicationEventPublisher applicationEventPublisher;
  private final BusProperties busProperties;

  protected void publishEvent(String destination, String key) {
    log.debug("Publishing test event with destination {} and key {}", destination, key);
    TestEvent testEvent = new TestEvent(this, busProperties.getId(), String.format("%s:**", destination), key);
    applicationEventPublisher.publishEvent(testEvent);
  }
}

Error logs

2025-12-02T08:34:15.636+03:00 ERROR 64774 --- [test-service] [uCnbIRZGKBk_Q-1] o.s.c.b.j.BusJacksonMessageConverter     : Cannot construct instance of `org.test.model.event.TestEvent`, problem: null source
 at [Source: REDACTED (`StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION` disabled); byte offset: spring-cloud/spring-cloud-bus#234]

tools.jackson.databind.exc.ValueInstantiationException: Cannot construct instance of `org.test.model.event.TestEvent`, problem: null source
 at [Source: REDACTED (`StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION` disabled); byte offset: spring-cloud/spring-cloud-bus#234]
	at tools.jackson.databind.exc.ValueInstantiationException.from(ValueInstantiationException.java:44) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.DeserializationContext.instantiationException(DeserializationContext.java:2080) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.std.StdValueInstantiator.wrapAsDatabindException(StdValueInstantiator.java:581) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.std.StdValueInstantiator.rewrapCtorProblem(StdValueInstantiator.java:602) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.std.StdValueInstantiator.createFromObjectWith(StdValueInstantiator.java:289) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.ValueInstantiator.createFromObjectWith(ValueInstantiator.java:270) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.bean.PropertyBasedCreator.build(PropertyBasedCreator.java:252) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.bean.BeanDeserializer._deserializeUsingPropertyBased(BeanDeserializer.java:697) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.bean.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1417) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.bean.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:480) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.bean.BeanDeserializer._deserializeOther(BeanDeserializer.java:235) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.bean.BeanDeserializer.deserialize(BeanDeserializer.java:202) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer._deserializeTypedForId(AsPropertyTypeDeserializer.java:138) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.jsontype.impl.AsPropertyTypeDeserializer.deserializeTypedFromObject(AsPropertyTypeDeserializer.java:103) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.AbstractDeserializer.deserializeWithType(AbstractDeserializer.java:243) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.impl.TypeWrappedDeserializer.deserialize(TypeWrappedDeserializer.java:72) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.DeserializationContextExt.readRootValue(DeserializationContextExt.java:265) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2610) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:1627) ~[jackson-databind-3.0.2.jar:3.0.2]
	at org.springframework.cloud.bus.jackson.BusJacksonMessageConverter.convertFromInternal(BusJacksonAutoConfiguration.java:180) ~[spring-cloud-bus-5.0.0.jar:5.0.0]
	at org.springframework.messaging.converter.AbstractMessageConverter.fromMessage(AbstractMessageConverter.java:179) ~[spring-messaging-7.0.1.jar:7.0.1]
	at org.springframework.messaging.converter.AbstractMessageConverter.fromMessage(AbstractMessageConverter.java:171) ~[spring-messaging-7.0.1.jar:7.0.1]
	at org.springframework.cloud.function.context.config.SmartCompositeMessageConverter.fromMessage(SmartCompositeMessageConverter.java:75) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.convertInputMessageIfNecessary(SimpleFunctionRegistry.java:1428) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.convertInputIfNecessary(SimpleFunctionRegistry.java:1180) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.doApply(SimpleFunctionRegistry.java:787) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.apply(SimpleFunctionRegistry.java:627) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.function.observability.ObservationFunctionAroundWrapper.lambda$nonReactorStream$0(ObservationFunctionAroundWrapper.java:50) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at io.micrometer.observation.Observation.observe(Observation.java:564) ~[micrometer-observation-1.16.0.jar:1.16.0]
	at org.springframework.cloud.function.observability.ObservationFunctionAroundWrapper.nonReactorStream(ObservationFunctionAroundWrapper.java:50) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.function.observability.ObservationFunctionAroundWrapper.doApply(ObservationFunctionAroundWrapper.java:45) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.function.context.catalog.FunctionAroundWrapper.apply(FunctionAroundWrapper.java:44) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry$FunctionInvocationWrapper.apply(SimpleFunctionRegistry.java:624) ~[spring-cloud-function-context-5.0.0.jar:5.0.0]
	at org.springframework.cloud.stream.function.PartitionAwareFunctionWrapper.apply(PartitionAwareFunctionWrapper.java:92) ~[spring-cloud-stream-5.0.0.jar:5.0.0]
	at org.springframework.cloud.stream.function.FunctionConfiguration$FunctionWrapper.apply(FunctionConfiguration.java:830) ~[spring-cloud-stream-5.0.0.jar:5.0.0]
	at org.springframework.cloud.stream.function.FunctionConfiguration$FunctionToDestinationBinder$1.handleMessageInternal(FunctionConfiguration.java:668) ~[spring-cloud-stream-5.0.0.jar:5.0.0]
	at org.springframework.integration.handler.AbstractMessageHandler.doHandleMessage(AbstractMessageHandler.java:102) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:70) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:133) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:150) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:123) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:72) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.channel.AbstractMessageChannel.sendInternal(AbstractMessageChannel.java:438) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.channel.AbstractMessageChannel.sendWithMetrics(AbstractMessageChannel.java:409) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:338) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:310) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187) ~[spring-messaging-7.0.1.jar:7.0.1]
	at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166) ~[spring-messaging-7.0.1.jar:7.0.1]
	at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47) ~[spring-messaging-7.0.1.jar:7.0.1]
	at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:108) ~[spring-messaging-7.0.1.jar:7.0.1]
	at org.springframework.integration.endpoint.MessageProducerSupport.sendMessageWithTracking(MessageProducerSupport.java:278) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.endpoint.MessageProducerSupport.sendMessage(MessageProducerSupport.java:267) ~[spring-integration-core-7.0.0.jar:7.0.0]
	at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter.access$000(AmqpInboundChannelAdapter.java:71) ~[spring-integration-amqp-7.0.0.jar:7.0.0]
	at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter$Listener.lambda$onMessage$0(AmqpInboundChannelAdapter.java:392) ~[spring-integration-amqp-7.0.0.jar:7.0.0]
	at org.springframework.core.retry.RetryTemplate.execute(RetryTemplate.java:142) ~[spring-core-7.0.1.jar:7.0.1]
	at org.springframework.integration.amqp.inbound.AmqpInboundChannelAdapter$Listener.onMessage(AmqpInboundChannelAdapter.java:385) ~[spring-integration-amqp-7.0.0.jar:7.0.0]
	at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:1683) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.actualInvokeListener(AbstractMessageListenerContainer.java:1612) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:1599) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:1590) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListenerAndHandleException(AbstractMessageListenerContainer.java:1539) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.lambda$executeListener$1(AbstractMessageListenerContainer.java:1517) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at io.micrometer.observation.Observation.observe(Observation.java:499) ~[micrometer-observation-1.16.0.jar:1.16.0]
	at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:1517) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:1116) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:1061) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.mainLoop(SimpleMessageListenerContainer.java:1465) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1359) ~[spring-rabbit-4.0.0.jar:4.0.0]
	at java.base/java.lang.Thread.run(Thread.java:1583) ~[na:na]
Caused by: java.lang.IllegalArgumentException: null source
	at java.base/java.util.EventObject.<init>(EventObject.java:57) ~[na:na]
	at org.springframework.context.ApplicationEvent.<init>(ApplicationEvent.java:48) ~[spring-context-7.0.1.jar:7.0.1]
	at org.springframework.cloud.bus.event.RemoteApplicationEvent.<init>(RemoteApplicationEvent.java:61) ~[spring-cloud-bus-5.0.0.jar:5.0.0]
	at org.test.model.event.TestEvent.<init>(TestEvent.java:16) ~[classes/:na]
	at java.base/java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:733) ~[na:na]
	at tools.jackson.databind.introspect.AnnotatedConstructor.call(AnnotatedConstructor.java:113) ~[jackson-databind-3.0.2.jar:3.0.2]
	at tools.jackson.databind.deser.std.StdValueInstantiator.createFromObjectWith(StdValueInstantiator.java:287) ~[jackson-databind-3.0.2.jar:3.0.2]
	... 64 common frames omitted