Fix Checkstyle violations

See gh-23784

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

@@ -295,9 +295,11 @@ public class ApplicationListenerMethodAdapter implements GenericApplicationListe
 	@Nullable
 	protected Object doInvoke(Object... args) {
 		Object bean = getTargetBean();
+		// Detect package-protected NullBean instance through equals(null) check
 		if (bean.equals(null)) {
 			return null;
 		}
+
 		ReflectionUtils.makeAccessible(this.method);
 		try {
 			return this.method.invoke(bean, args);

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

@@ -16,8 +16,6 @@
 
 package org.springframework.context.event;
 
-import java.io.Closeable;
-import java.io.IOException;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -627,12 +625,13 @@ public class AnnotationDrivenEventListenerTests {
 	}
 
 	@Test
-	public void missingBeanDoesntCrash() {
+	public void missingListenerBeanIgnored() {
 		load(MissingEventListener.class);
 		context.getBean(UseMissingEventListener.class);
 		context.getBean(ApplicationEventMulticaster.class).multicastEvent(new TestEvent(this));
 	}
 
+
 	private void load(Class<?>... classes) {
 		List<Class<?>> allClasses = new ArrayList<>();
 		allClasses.add(BasicConfiguration.class);
@@ -1087,8 +1086,9 @@ public class AnnotationDrivenEventListenerTests {
 	}
 
 	@Configuration
-	@Import({UseMissingEventListener.class})
+	@Import(UseMissingEventListener.class)
 	public static class MissingEventListener {
+
 		@Bean
 		public MyEventListener missing() {
 			return null;
@@ -1096,17 +1096,16 @@ public class AnnotationDrivenEventListenerTests {
 	}
 
 	@Component
-	public static class MyEventListener implements Closeable {
+	public static class MyEventListener {
+
 		@EventListener
 		public void hear(TestEvent e) {
 			throw new AssertionError();
 		}
-
-	    @Override
-	    public void close() throws IOException {}
 	}
 
 	public static class UseMissingEventListener {
+
 		@Inject
 		public UseMissingEventListener(Optional<MyEventListener> notHere) {
 			if (notHere.isPresent()) {
@@ -1114,4 +1113,5 @@ public class AnnotationDrivenEventListenerTests {
 			}
 		}
 	}
+
 }