Clean up warnings and polishing

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/DeferredResultMethodReturnValueHandler.java

@@ -21,8 +21,6 @@ import java.util.concurrent.CompletionStage;
 
 import org.springframework.core.MethodParameter;
 import org.springframework.lang.Nullable;
-import org.springframework.util.concurrent.ListenableFuture;
-import org.springframework.util.concurrent.ListenableFutureCallback;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.request.async.DeferredResult;
 import org.springframework.web.context.request.async.WebAsyncUtils;
@@ -31,7 +29,8 @@ import org.springframework.web.method.support.ModelAndViewContainer;
 
 /**
  * Handler for return values of type {@link DeferredResult},
- * {@link ListenableFuture}, and {@link CompletionStage}.
+ * {@link org.springframework.util.concurrent.ListenableFuture}, and
+ * {@link CompletionStage}.
  *
  * @author Rossen Stoyanchev
  * @since 3.2
@@ -43,7 +42,7 @@ public class DeferredResultMethodReturnValueHandler implements HandlerMethodRetu
 	public boolean supportsReturnType(MethodParameter returnType) {
 		Class<?> type = returnType.getParameterType();
 		return (DeferredResult.class.isAssignableFrom(type) ||
-				ListenableFuture.class.isAssignableFrom(type) ||
+				org.springframework.util.concurrent.ListenableFuture.class.isAssignableFrom(type) ||
 				CompletionStage.class.isAssignableFrom(type));
 	}
 
@@ -59,14 +58,14 @@ public class DeferredResultMethodReturnValueHandler implements HandlerMethodRetu
 
 		DeferredResult<?> result;
 
-		if (returnValue instanceof DeferredResult) {
-			result = (DeferredResult<?>) returnValue;
+		if (returnValue instanceof DeferredResult<?> deferredResult) {
+			result = deferredResult;
 		}
-		else if (returnValue instanceof ListenableFuture) {
-			result = adaptListenableFuture((ListenableFuture<?>) returnValue);
+		else if (returnValue instanceof org.springframework.util.concurrent.ListenableFuture<?> listenableFuture) {
+			result = adaptListenableFuture(listenableFuture);
 		}
-		else if (returnValue instanceof CompletionStage) {
-			result = adaptCompletionStage((CompletionStage<?>) returnValue);
+		else if (returnValue instanceof CompletionStage<?> completionStage) {
+			result = adaptCompletionStage(completionStage);
 		}
 		else {
 			// Should not happen...
@@ -77,9 +76,9 @@ public class DeferredResultMethodReturnValueHandler implements HandlerMethodRetu
 	}
 
 	@SuppressWarnings("deprecation")
-	private DeferredResult<Object> adaptListenableFuture(ListenableFuture<?> future) {
+	private DeferredResult<Object> adaptListenableFuture(org.springframework.util.concurrent.ListenableFuture<?> future) {
 		DeferredResult<Object> result = new DeferredResult<>();
-		future.addCallback(new ListenableFutureCallback<Object>() {
+		future.addCallback(new org.springframework.util.concurrent.ListenableFutureCallback<Object>() {
 			@Override
 			public void onSuccess(@Nullable Object value) {
 				result.setResult(value);

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/DeferredResultReturnValueHandlerTests.java

@@ -22,8 +22,6 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.core.MethodParameter;
-import org.springframework.util.concurrent.ListenableFuture;
-import org.springframework.util.concurrent.SettableListenableFuture;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.request.ServletWebRequest;
 import org.springframework.web.context.request.async.AsyncWebRequest;
@@ -65,12 +63,13 @@ public class DeferredResultReturnValueHandlerTests {
 
 
 	@Test
+	@SuppressWarnings("deprecation")
 	public void supportsReturnType() throws Exception {
 		assertThat(this.handler.supportsReturnType(
 				on(TestController.class).resolveReturnType(DeferredResult.class, String.class))).isTrue();
 
 		assertThat(this.handler.supportsReturnType(
-				on(TestController.class).resolveReturnType(ListenableFuture.class, String.class))).isTrue();
+				on(TestController.class).resolveReturnType(org.springframework.util.concurrent.ListenableFuture.class, String.class))).isTrue();
 
 		assertThat(this.handler.supportsReturnType(
 				on(TestController.class).resolveReturnType(CompletableFuture.class, String.class))).isTrue();
@@ -91,8 +90,10 @@ public class DeferredResultReturnValueHandlerTests {
 	@Test
 	@SuppressWarnings("deprecation")
 	public void listenableFuture() throws Exception {
-		SettableListenableFuture<String> future = new SettableListenableFuture<>();
-		testHandle(future, ListenableFuture.class, () -> future.set("foo"), "foo");
+		org.springframework.util.concurrent.SettableListenableFuture<String> future =
+				new org.springframework.util.concurrent.SettableListenableFuture<>();
+		testHandle(future, org.springframework.util.concurrent.ListenableFuture.class,
+				() -> future.set("foo"), "foo");
 	}
 
 	@Test
@@ -110,9 +111,11 @@ public class DeferredResultReturnValueHandlerTests {
 	@Test
 	@SuppressWarnings("deprecation")
 	public void listenableFutureWithError() throws Exception {
-		SettableListenableFuture<String> future = new SettableListenableFuture<>();
+		org.springframework.util.concurrent.SettableListenableFuture<String> future =
+				new org.springframework.util.concurrent.SettableListenableFuture<>();
 		IllegalStateException ex = new IllegalStateException();
-		testHandle(future, ListenableFuture.class, () -> future.setException(ex), ex);
+		testHandle(future, org.springframework.util.concurrent.ListenableFuture.class,
+				() -> future.setException(ex), ex);
 	}
 
 	@Test
@@ -147,7 +150,8 @@ public class DeferredResultReturnValueHandlerTests {
 
 		DeferredResult<String> handleDeferredResult() { return null; }
 
-		ListenableFuture<String> handleListenableFuture() { return null; }
+		@SuppressWarnings("deprecation")
+		org.springframework.util.concurrent.ListenableFuture<String> handleListenableFuture() { return null; }
 
 		CompletableFuture<String> handleCompletableFuture() { return null; }
 	}