Only use payload if it actually matches declared event type

Closes gh-22426

Author: jhoeller

spring-context/src/main/java/org/springframework/context/event/ApplicationListenerMethodAdapter.java

@@ -186,9 +186,9 @@ public void processEvent(ApplicationEvent event) {
 
 	/**
 	 * Resolve the method arguments to use for the specified {@link ApplicationEvent}.
-	 * <p>These arguments will be used to invoke the method handled by this instance. Can
-	 * return {@code null} to indicate that no suitable arguments could be resolved and
-	 * therefore the method should not be invoked at all for the specified event.
+	 * <p>These arguments will be used to invoke the method handled by this instance.
+	 * Can return {@code null} to indicate that no suitable arguments could be resolved
+	 * and therefore the method should not be invoked at all for the specified event.
 	 */
 	protected Object[] resolveArguments(ApplicationEvent event) {
 		ResolvableType declaredEventType = getResolvableType(event);
@@ -198,13 +198,15 @@ protected Object[] resolveArguments(ApplicationEvent event) {
 		if (this.method.getParameterTypes().length == 0) {
 			return new Object[0];
 		}
-		if (!ApplicationEvent.class.isAssignableFrom(declaredEventType.getRawClass()) &&
+		Class<?> eventClass = declaredEventType.getRawClass();
+		if ((eventClass == null || !ApplicationEvent.class.isAssignableFrom(eventClass)) &&
 				event instanceof PayloadApplicationEvent) {
-			return new Object[] {((PayloadApplicationEvent) event).getPayload()};
-		}
-		else {
-			return new Object[] {event};
+			Object payload = ((PayloadApplicationEvent) event).getPayload();
+			if (eventClass == null || eventClass.isInstance(payload)) {
+				return new Object[] {payload};
+			}
 		}
+		return new Object[] {event};
 	}
 
 	protected void handleResult(Object result) {

spring-context/src/test/java/org/springframework/context/event/PayloadApplicationEventTests.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.context.event;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.Test;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.PayloadApplicationEvent;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.stereotype.Component;
+
+import static org.junit.Assert.*;
+
+/**
+ * @author Juergen Hoeller
+ */
+public class PayloadApplicationEventTests {
+
+	@Test
+	public void testEventClassWithInterface() {
+		ApplicationContext ac = new AnnotationConfigApplicationContext(Listener.class);
+		MyEventClass event = new MyEventClass<>(this, "xyz");
+		ac.publishEvent(event);
+		assertTrue(ac.getBean(Listener.class).events.contains(event));
+	}
+
+
+	public interface Auditable {
+	}
+
+
+	public static class MyEventClass<GT> extends PayloadApplicationEvent<GT> implements Auditable {
+
+		public MyEventClass(Object source, GT payload) {
+			super(source, payload);
+		}
+
+		public String toString() {
+			return "Payload: " + getPayload();
+		}
+	}
+
+
+	@Component
+	public static class Listener {
+
+		public final List<Auditable> events = new ArrayList<>();
+
+		@EventListener
+		public void onEvent(Auditable event) {
+			events.add(event);
+		}
+	}
+
+}