From 0296d003af5aa45d489af4c3dd43945e60954c4a Mon Sep 17 00:00:00 2001
From: Rossen Stoyanchev <rstoyanchev@pivotal.io>
Date: Sun, 5 Mar 2017 18:10:45 -0500
Subject: [PATCH] Improved generics support in ResolvableMethod

---
 .../web/method/ResolvableMethod.java          | 194 ++++++++++++------
 ...questParamMethodArgumentResolverTests.java |  54 ++---
 .../MessageWriterResultHandlerTests.java      |  38 ++--
 ...lAttributeMethodArgumentResolverTests.java |  37 ++--
 .../RequestBodyArgumentResolverTests.java     |  56 ++---
 ...questParamMethodArgumentResolverTests.java |   4 -
 .../ResponseEntityResultHandlerTests.java     |  32 ++-
 .../ViewResolutionResultHandlerTests.java     |  36 ++--
 8 files changed, 234 insertions(+), 217 deletions(-)

diff --git a/spring-web/src/test/java/org/springframework/web/method/ResolvableMethod.java b/spring-web/src/test/java/org/springframework/web/method/ResolvableMethod.java
index 103b10465ba..fc5aef04866 100644
--- a/spring-web/src/test/java/org/springframework/web/method/ResolvableMethod.java
+++ b/spring-web/src/test/java/org/springframework/web/method/ResolvableMethod.java
@@ -38,18 +38,21 @@ import org.springframework.cglib.proxy.Callback;
 import org.springframework.cglib.proxy.Enhancer;
 import org.springframework.cglib.proxy.Factory;
 import org.springframework.cglib.proxy.MethodProxy;
+import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
 import org.springframework.core.MethodIntrospector;
 import org.springframework.core.MethodParameter;
+import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.annotation.SynthesizingMethodParameter;
 import org.springframework.objenesis.ObjenesisException;
 import org.springframework.objenesis.SpringObjenesis;
 import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
 import org.springframework.util.ReflectionUtils;
 
 /**
- * Convenience class to resolve a method and its parameters based on hints.
+ * Convenience class to resolve method parameters from hints.
  *
  * <h1>Background</h1>
  *
@@ -57,19 +60,15 @@ import org.springframework.util.ReflectionUtils;
  * "TestController" with a diverse range of method signatures representing
  * supported annotations and argument types. It becomes challenging to use
  * naming strategies to keep track of methods and arguments especially in
- * combination variables for reflection metadata.
+ * combination with variables for reflection metadata.
  *
  * <p>The idea with {@link ResolvableMethod} is NOT to rely on naming techniques
- * but to use hints to zero in on method parameters. Especially in combination
- * with {@link ResolvableType} such hints can be strongly typed and make tests
- * more readable by being explicit about what is being tested and more robust
- * since the provided hints have to match.
- *
- * <p>Common use cases:
+ * but to use hints to zero in on method parameters. Such hints can be strongly
+ * typed and explicit about what is being tested.
  *
  * <h2>1. Declared Return Type</h2>
  *
- * When testing return types it's common to have many methods with a unique
+ * When testing return types it's likely to have many methods with a unique
  * return type, possibly with or without an annotation.
  *
  * <pre>
@@ -78,6 +77,8 @@ import org.springframework.util.ReflectionUtils;
  *
  * // Return type
  * on(TestController.class).resolveReturnType(Foo.class);
+ * on(TestController.class).resolveReturnType(List.class, Foo.class);
+ * on(TestController.class).resolveReturnType(Mono.class, responseEntity(Foo.class));
  *
  * // Annotation + return type
  * on(TestController.class).annotated(ResponseBody.class).resolveReturnType(Bar.class);
@@ -85,7 +86,7 @@ import org.springframework.util.ReflectionUtils;
  * // Annotation not present
  * on(TestController.class).notAnnotated(ResponseBody.class).resolveReturnType();
  *
- * // Annotation properties
+ * // Annotation with attributes
  * on(TestController.class)
  *         .annotated(RequestMapping.class, patterns("/foo"), params("p"))
  *         .annotated(ResponseBody.class)
@@ -124,6 +125,9 @@ public class ResolvableMethod {
 
 	private static final SpringObjenesis objenesis = new SpringObjenesis();
 
+	private static final ParameterNameDiscoverer nameDiscoverer =
+			new LocalVariableTableParameterNameDiscoverer();
+
 
 	private final Method method;
 
@@ -151,9 +155,20 @@ public class ResolvableMethod {
 	/**
 	 * Find a unique argument matching the given type.
 	 * @param type the expected type
+	 * @param generics optional array of generic types
 	 */
-	public MethodParameter arg(Class<?> type) {
-		return new ArgResolver().arg(type);
+	public MethodParameter arg(Class<?> type, Class<?>... generics) {
+		return new ArgResolver().arg(type, generics);
+	}
+
+	/**
+	 * Find a unique argument matching the given type.
+	 * @param type the expected type
+	 * @param generic at least one generic type
+	 * @param generics optional array of generic types
+	 */
+	public MethodParameter arg(Class<?> type, ResolvableType generic, ResolvableType... generics) {
+		return new ArgResolver().arg(type, generic, generics);
 	}
 
 	/**
@@ -207,6 +222,19 @@ public class ResolvableMethod {
 						.collect(Collectors.joining(",\n\t", "(\n\t", "\n)"));
 	}
 
+	private static ResolvableType toResolvableType(Class<?> type, Class<?>... generics) {
+		return ObjectUtils.isEmpty(generics) ?
+				ResolvableType.forClass(type) :
+				ResolvableType.forClassWithGenerics(type, generics);
+	}
+
+	private static ResolvableType toResolvableType(Class<?> type, ResolvableType generic, ResolvableType... generics) {
+		ResolvableType[] genericTypes = new ResolvableType[generics.length + 1];
+		genericTypes[0] = generic;
+		System.arraycopy(generics, 0, genericTypes, 1, generics.length);
+		return ResolvableType.forClassWithGenerics(type, genericTypes);
+	}
+
 
 	/**
 	 * Main entry point providing access to a {@code ResolvableMethod} builder.
@@ -278,16 +306,29 @@ public class ResolvableMethod {
 
 		/**
 		 * Filter on methods returning the given type.
+		 * @param returnType the return type
+		 * @param generics optional array of generic types
+		 */
+		public Builder returning(Class<?> returnType, Class<?>... generics) {
+			return returning(toResolvableType(returnType, generics));
+		}
+
+		/**
+		 * Filter on methods returning the given type with generics.
+		 * @param returnType the return type
+		 * @param generic at least one generic type
+		 * @param generics optional extra generic types
 		 */
-		public Builder returning(Class<?> returnType) {
-			return returning(ResolvableType.forClass(returnType));
+		public Builder returning(Class<?> returnType, ResolvableType generic, ResolvableType... generics) {
+			return returning(toResolvableType(returnType, generic, generics));
 		}
 
 		/**
 		 * Filter on methods returning the given type.
+		 * @param returnType the return type
 		 */
-		public Builder returning(ResolvableType resolvableType) {
-			String expected = resolvableType.toString();
+		public Builder returning(ResolvableType returnType) {
+			String expected = returnType.toString();
 			String message = "returnType=" + expected;
 			addFilter(message, m -> expected.equals(ResolvableType.forMethodReturnType(m).toString()));
 			return this;
@@ -336,7 +377,7 @@ public class ResolvableMethod {
 		}
 
 
-		// Build & Resolve shortcuts...
+		// Build & resolve shortcuts...
 
 		/**
 		 * Resolve and return the {@code Method} equivalent to:
@@ -365,15 +406,26 @@ public class ResolvableMethod {
 		/**
 		 * Shortcut to the unique return type equivalent to:
 		 * <p>{@code returning(returnType).build().returnType()}
+		 * @param returnType the return type
+		 * @param generics optional array of generic types
 		 */
-		public MethodParameter resolveReturnType(Class<?> returnType) {
-			return returning(returnType).build().returnType();
+		public MethodParameter resolveReturnType(Class<?> returnType, Class<?>... generics) {
+			return returning(returnType, generics).build().returnType();
 		}
 
 		/**
 		 * Shortcut to the unique return type equivalent to:
 		 * <p>{@code returning(returnType).build().returnType()}
+		 * @param returnType the return type
+		 * @param generic at least one generic type
+		 * @param generics optional extra generic types
 		 */
+		public MethodParameter resolveReturnType(Class<?> returnType, ResolvableType generic,
+				ResolvableType... generics) {
+
+			return returning(returnType, generic, generics).build().returnType();
+		}
+
 		public MethodParameter resolveReturnType(ResolvableType returnType) {
 			return returning(returnType).build().returnType();
 		}
@@ -392,51 +444,6 @@ public class ResolvableMethod {
 		}
 	}
 
-	@SuppressWarnings("unchecked")
-	private static <T> T initProxy(Class<?> type, MethodInvocationInterceptor interceptor) {
-		Assert.notNull(type, "'type' must not be null");
-		if (type.isInterface()) {
-			ProxyFactory factory = new ProxyFactory(EmptyTargetSource.INSTANCE);
-			factory.addInterface(type);
-			factory.addInterface(Supplier.class);
-			factory.addAdvice(interceptor);
-			return (T) factory.getProxy();
-		}
-
-		else {
-			Enhancer enhancer = new Enhancer();
-			enhancer.setSuperclass(type);
-			enhancer.setInterfaces(new Class<?>[] {Supplier.class});
-			enhancer.setNamingPolicy(SpringNamingPolicy.INSTANCE);
-			enhancer.setCallbackType(org.springframework.cglib.proxy.MethodInterceptor.class);
-
-			Class<?> proxyClass = enhancer.createClass();
-			Object proxy = null;
-
-			if (objenesis.isWorthTrying()) {
-				try {
-					proxy = objenesis.newInstance(proxyClass, enhancer.getUseCache());
-				}
-				catch (ObjenesisException ex) {
-					logger.debug("Objenesis failed, falling back to default constructor", ex);
-				}
-			}
-
-			if (proxy == null) {
-				try {
-					proxy = ReflectionUtils.accessibleConstructor(proxyClass).newInstance();
-				}
-				catch (Throwable ex) {
-					throw new IllegalStateException("Unable to instantiate proxy " +
-							"via both Objenesis and default constructor fails as well", ex);
-				}
-			}
-
-			((Factory) proxy).setCallbacks(new Callback[] {interceptor});
-			return (T) proxy;
-		}
-	}
-
 	/**
 	 * Predicate with a descriptive label.
 	 */
@@ -533,9 +540,16 @@ public class ResolvableMethod {
 		 * Resolve the argument also matching to the given type.
 		 * @param type the expected type
 		 */
-		public MethodParameter arg(Class<?> type) {
-			this.filters.add(p -> type.equals(p.getParameterType()));
-			return arg(ResolvableType.forClass(type));
+		public MethodParameter arg(Class<?> type, Class<?>... generics) {
+			return arg(toResolvableType(type, generics));
+		}
+
+		/**
+		 * Resolve the argument also matching to the given type.
+		 * @param type the expected type
+		 */
+		public MethodParameter arg(Class<?> type, ResolvableType generic, ResolvableType... generics) {
+			return arg(toResolvableType(type, generic, generics));
 		}
 
 		/**
@@ -562,6 +576,7 @@ public class ResolvableMethod {
 			List<MethodParameter> matches = new ArrayList<>();
 			for (int i = 0; i < method.getParameterCount(); i++) {
 				MethodParameter param = new SynthesizingMethodParameter(method, i);
+				param.initParameterNameDiscovery(nameDiscoverer);
 				if (this.filters.stream().allMatch(p -> p.test(param))) {
 					matches.add(param);
 				}
@@ -597,4 +612,49 @@ public class ResolvableMethod {
 		}
 	}
 
+	@SuppressWarnings("unchecked")
+	private static <T> T initProxy(Class<?> type, MethodInvocationInterceptor interceptor) {
+		Assert.notNull(type, "'type' must not be null");
+		if (type.isInterface()) {
+			ProxyFactory factory = new ProxyFactory(EmptyTargetSource.INSTANCE);
+			factory.addInterface(type);
+			factory.addInterface(Supplier.class);
+			factory.addAdvice(interceptor);
+			return (T) factory.getProxy();
+		}
+
+		else {
+			Enhancer enhancer = new Enhancer();
+			enhancer.setSuperclass(type);
+			enhancer.setInterfaces(new Class<?>[] {Supplier.class});
+			enhancer.setNamingPolicy(SpringNamingPolicy.INSTANCE);
+			enhancer.setCallbackType(org.springframework.cglib.proxy.MethodInterceptor.class);
+
+			Class<?> proxyClass = enhancer.createClass();
+			Object proxy = null;
+
+			if (objenesis.isWorthTrying()) {
+				try {
+					proxy = objenesis.newInstance(proxyClass, enhancer.getUseCache());
+				}
+				catch (ObjenesisException ex) {
+					logger.debug("Objenesis failed, falling back to default constructor", ex);
+				}
+			}
+
+			if (proxy == null) {
+				try {
+					proxy = ReflectionUtils.accessibleConstructor(proxyClass).newInstance();
+				}
+				catch (Throwable ex) {
+					throw new IllegalStateException("Unable to instantiate proxy " +
+							"via both Objenesis and default constructor fails as well", ex);
+				}
+			}
+
+			((Factory) proxy).setCallbacks(new Callback[] {interceptor});
+			return (T) proxy;
+		}
+	}
+
 }
diff --git a/spring-web/src/test/java/org/springframework/web/method/annotation/RequestParamMethodArgumentResolverTests.java b/spring-web/src/test/java/org/springframework/web/method/annotation/RequestParamMethodArgumentResolverTests.java
index 21f0e731118..91294f258d2 100644
--- a/spring-web/src/test/java/org/springframework/web/method/annotation/RequestParamMethodArgumentResolverTests.java
+++ b/spring-web/src/test/java/org/springframework/web/method/annotation/RequestParamMethodArgumentResolverTests.java
@@ -27,7 +27,6 @@ import org.junit.Before;
 import org.junit.Test;
 
 import org.springframework.beans.propertyeditors.StringTrimmerEditor;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.mock.web.test.MockHttpServletRequest;
@@ -59,7 +58,6 @@ import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.BDDMockito.mock;
-import static org.springframework.core.ResolvableType.forClassWithGenerics;
 
 /**
  * Test fixture with {@link org.springframework.web.method.annotation.RequestParamMethodArgumentResolver}.
@@ -101,7 +99,7 @@ public class RequestParamMethodArgumentResolverTests {
 		param = this.testMethod.annotated(RequestParam.class).arg(MultipartFile.class);
 		assertTrue(resolver.supportsParameter(param));
 
-		param = this.testMethod.annotated(RequestParam.class).arg(forClassWithGenerics(List.class, MultipartFile.class));
+		param = this.testMethod.annotated(RequestParam.class).arg(List.class, MultipartFile.class);
 		assertTrue(resolver.supportsParameter(param));
 
 		param = this.testMethod.annotated(RequestParam.class).arg(MultipartFile[].class);
@@ -110,7 +108,7 @@ public class RequestParamMethodArgumentResolverTests {
 		param = this.testMethod.annotated(RequestParam.class).arg(Part.class);
 		assertTrue(resolver.supportsParameter(param));
 
-		param = this.testMethod.annotated(RequestParam.class).arg(forClassWithGenerics(List.class, Part.class));
+		param = this.testMethod.annotated(RequestParam.class).arg(List.class, Part.class);
 		assertTrue(resolver.supportsParameter(param));
 
 		param = this.testMethod.annotated(RequestParam.class).arg(Part[].class);
@@ -125,7 +123,7 @@ public class RequestParamMethodArgumentResolverTests {
 		param = this.testMethod.notAnnotated().arg(MultipartFile.class);
 		assertTrue(resolver.supportsParameter(param));
 
-		param = this.testMethod.notAnnotated(RequestParam.class).arg(forClassWithGenerics(List.class, MultipartFile.class));
+		param = this.testMethod.notAnnotated(RequestParam.class).arg(List.class, MultipartFile.class);
 		assertTrue(resolver.supportsParameter(param));
 
 		param = this.testMethod.notAnnotated(RequestParam.class).arg(Part.class);
@@ -140,10 +138,10 @@ public class RequestParamMethodArgumentResolverTests {
 		param = this.testMethod.annotated(RequestParam.class, required().negate()).arg(String.class);
 		assertTrue(resolver.supportsParameter(param));
 
-		param = this.testMethod.annotated(RequestParam.class).arg(forClassWithGenerics(Optional.class, Integer.class));
+		param = this.testMethod.annotated(RequestParam.class).arg(Optional.class, Integer.class);
 		assertTrue(resolver.supportsParameter(param));
 
-		param = this.testMethod.annotated(RequestParam.class).arg(forClassWithGenerics(Optional.class, MultipartFile.class));
+		param = this.testMethod.annotated(RequestParam.class).arg(Optional.class, MultipartFile.class);
 		assertTrue(resolver.supportsParameter(param));
 
 		resolver = new RequestParamMethodArgumentResolver(null, false);
@@ -201,8 +199,7 @@ public class RequestParamMethodArgumentResolverTests {
 		webRequest = new ServletWebRequest(request);
 
 		MethodParameter param = this.testMethod
-				.annotated(RequestParam.class)
-				.arg(forClassWithGenerics(List.class, MultipartFile.class));
+				.annotated(RequestParam.class).arg(List.class, MultipartFile.class);
 
 		Object result = resolver.resolveArgument(param, null, webRequest, null);
 		assertTrue(result instanceof List);
@@ -255,10 +252,7 @@ public class RequestParamMethodArgumentResolverTests {
 		request.addPart(new MockPart("other", "Hello World 3".getBytes()));
 		webRequest = new ServletWebRequest(request);
 
-		MethodParameter param = this.testMethod
-				.annotated(RequestParam.class)
-				.arg(forClassWithGenerics(List.class, Part.class));
-
+		MethodParameter param = this.testMethod.annotated(RequestParam.class).arg(List.class, Part.class);
 		Object result = resolver.resolveArgument(param, null, webRequest, null);
 		assertTrue(result instanceof List);
 		assertEquals(Arrays.asList(expected1, expected2), result);
@@ -293,8 +287,6 @@ public class RequestParamMethodArgumentResolverTests {
 		webRequest = new ServletWebRequest(request);
 
 		MethodParameter param = this.testMethod.notAnnotated().arg(MultipartFile.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
-
 		Object result = resolver.resolveArgument(param, null, webRequest, null);
 		assertTrue(result instanceof MultipartFile);
 		assertEquals("Invalid result", expected, result);
@@ -310,9 +302,7 @@ public class RequestParamMethodArgumentResolverTests {
 		webRequest = new ServletWebRequest(request);
 
 		MethodParameter param = this.testMethod
-				.notAnnotated(RequestParam.class)
-				.arg(forClassWithGenerics(List.class, MultipartFile.class));
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
+				.notAnnotated(RequestParam.class).arg(List.class, MultipartFile.class);
 
 		Object result = resolver.resolveArgument(param, null, webRequest, null);
 		assertTrue(result instanceof List);
@@ -335,9 +325,7 @@ public class RequestParamMethodArgumentResolverTests {
 		webRequest = new ServletWebRequest(request);
 
 		MethodParameter param = this.testMethod
-				.notAnnotated(RequestParam.class)
-				.arg(forClassWithGenerics(List.class, MultipartFile.class));
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
+				.notAnnotated(RequestParam.class).arg(List.class, MultipartFile.class);
 
 		Object actual = resolver.resolveArgument(param, null, webRequest, null);
 		assertTrue(actual instanceof List);
@@ -371,7 +359,6 @@ public class RequestParamMethodArgumentResolverTests {
 		webRequest = new ServletWebRequest(request);
 
 		MethodParameter param = this.testMethod.notAnnotated(RequestParam.class).arg(Part.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 		Object result = resolver.resolveArgument(param, null, webRequest, null);
 		assertTrue(result instanceof Part);
 		assertEquals("Invalid result", expected, result);
@@ -403,7 +390,6 @@ public class RequestParamMethodArgumentResolverTests {
 		this.request.addParameter("stringNotAnnot", "");
 
 		MethodParameter param = this.testMethod.notAnnotated(RequestParam.class).arg(String.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 		Object arg = resolver.resolveArgument(param, null, webRequest, binderFactory);
 		assertNull(arg);
 	}
@@ -427,9 +413,7 @@ public class RequestParamMethodArgumentResolverTests {
 	public void resolveSimpleTypeParam() throws Exception {
 		request.setParameter("stringNotAnnot", "plainValue");
 		MethodParameter param = this.testMethod.notAnnotated(RequestParam.class).arg(String.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 		Object result = resolver.resolveArgument(param, null, webRequest, null);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 
 		assertTrue(result instanceof String);
 		assertEquals("plainValue", result);
@@ -438,7 +422,6 @@ public class RequestParamMethodArgumentResolverTests {
 	@Test  // SPR-8561
 	public void resolveSimpleTypeParamToNull() throws Exception {
 		MethodParameter param = this.testMethod.notAnnotated(RequestParam.class).arg(String.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 		Object result = resolver.resolveArgument(param, null, webRequest, null);
 		assertNull(result);
 	}
@@ -455,7 +438,6 @@ public class RequestParamMethodArgumentResolverTests {
 	public void resolveEmptyValueWithoutDefault() throws Exception {
 		this.request.addParameter("stringNotAnnot", "");
 		MethodParameter param = this.testMethod.notAnnotated(RequestParam.class).arg(String.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 		Object result = resolver.resolveArgument(param, null, webRequest, null);
 		assertEquals("", result);
 	}
@@ -476,8 +458,7 @@ public class RequestParamMethodArgumentResolverTests {
 		WebDataBinderFactory binderFactory = new DefaultDataBinderFactory(initializer);
 
 		MethodParameter param = this.testMethod
-				.annotated(RequestParam.class)
-				.arg(forClassWithGenerics(Optional.class, Integer.class));
+				.annotated(RequestParam.class).arg(Optional.class, Integer.class);
 
 		Object result = resolver.resolveArgument(param, null, webRequest, binderFactory);
 		assertEquals(Optional.empty(), result);
@@ -500,8 +481,7 @@ public class RequestParamMethodArgumentResolverTests {
 		webRequest = new ServletWebRequest(request);
 
 		MethodParameter param = this.testMethod
-				.annotated(RequestParam.class)
-				.arg(forClassWithGenerics(Optional.class, MultipartFile.class));
+				.annotated(RequestParam.class).arg(Optional.class, MultipartFile.class);
 
 		Object result = resolver.resolveArgument(param, null, webRequest, binderFactory);
 		assertTrue(result instanceof Optional);
@@ -518,10 +498,10 @@ public class RequestParamMethodArgumentResolverTests {
 		request.setContentType("multipart/form-data");
 
 		MethodParameter param = this.testMethod
-				.annotated(RequestParam.class)
-				.arg(forClassWithGenerics(Optional.class, MultipartFile.class));
+				.annotated(RequestParam.class).arg(Optional.class, MultipartFile.class);
 
-		assertEquals(Optional.empty(), resolver.resolveArgument(param, null, webRequest, binderFactory));
+		Object actual = resolver.resolveArgument(param, null, webRequest, binderFactory);
+		assertEquals(Optional.empty(), actual);
 	}
 
 	@Test
@@ -531,10 +511,10 @@ public class RequestParamMethodArgumentResolverTests {
 		WebDataBinderFactory binderFactory = new DefaultDataBinderFactory(initializer);
 
 		MethodParameter param = this.testMethod
-				.annotated(RequestParam.class)
-				.arg(forClassWithGenerics(Optional.class, MultipartFile.class));
+				.annotated(RequestParam.class).arg(Optional.class, MultipartFile.class);
 
-		assertEquals(Optional.empty(), resolver.resolveArgument(param, null, webRequest, binderFactory));
+		Object actual = resolver.resolveArgument(param, null, webRequest, binderFactory);
+		assertEquals(Optional.empty(), actual);
 	}
 
 	private Predicate<RequestParam> name(String name) {
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/MessageWriterResultHandlerTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/MessageWriterResultHandlerTests.java
index 4fd27a0d6f2..b5c3eb12cf1 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/MessageWriterResultHandlerTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/MessageWriterResultHandlerTests.java
@@ -59,11 +59,10 @@ import org.springframework.web.server.adapter.DefaultServerWebExchange;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
-import static org.springframework.core.ResolvableType.forClassWithGenerics;
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 import static org.springframework.http.MediaType.APPLICATION_JSON_UTF8;
-import static org.springframework.web.reactive.HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE;
 import static org.springframework.web.method.ResolvableMethod.on;
+import static org.springframework.web.reactive.HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE;
 
 /**
  * Unit tests for {@link AbstractMessageWriterResultHandler}.
@@ -110,27 +109,19 @@ public class MessageWriterResultHandlerTests {
 	@Test
 	public void voidReturnType() throws Exception {
 		testVoid(null, on(TestController.class).resolveReturnType(void.class));
+		testVoid(Mono.empty(), on(TestController.class).resolveReturnType(Mono.class, Void.class));
+		testVoid(Flux.empty(), on(TestController.class).resolveReturnType(Flux.class, Void.class));
+		testVoid(Completable.complete(), on(TestController.class).resolveReturnType(Completable.class));
+		testVoid(Observable.empty(), on(TestController.class).resolveReturnType(Observable.class, Void.class));
 
-		testVoid(Mono.empty(), on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(Mono.class, Void.class)));
-
-		testVoid(Flux.empty(), on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(Flux.class, Void.class)));
-
-		testVoid(Completable.complete(), on(TestController.class)
-				.resolveReturnType(Completable.class));
+		MethodParameter type = on(TestController.class).resolveReturnType(io.reactivex.Completable.class);
+		testVoid(io.reactivex.Completable.complete(), type);
 
-		testVoid(Observable.empty(), on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(Observable.class, Void.class)));
+		type = on(TestController.class).resolveReturnType(io.reactivex.Observable.class, Void.class);
+		testVoid(io.reactivex.Observable.empty(), type);
 
-		testVoid(io.reactivex.Completable.complete(), on(TestController.class)
-				.resolveReturnType(io.reactivex.Completable.class));
-
-		testVoid(io.reactivex.Observable.empty(), on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(io.reactivex.Observable.class, Void.class)));
-
-		testVoid(Flowable.empty(), on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(Flowable.class, Void.class)));
+		type = on(TestController.class).resolveReturnType(Flowable.class, Void.class);
+		testVoid(Flowable.empty(), type);
 	}
 
 	private void testVoid(Object body, MethodParameter returnType) {
@@ -155,9 +146,7 @@ public class MessageWriterResultHandlerTests {
 	@Test  // SPR-12811
 	public void jacksonTypeOfListElement() throws Exception {
 
-		MethodParameter returnType = on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(List.class, ParentClass.class));
-
+		MethodParameter returnType = on(TestController.class).resolveReturnType(List.class, ParentClass.class);
 		List<ParentClass> body = Arrays.asList(new Foo("foo"), new Bar("bar"));
 		this.resultHandler.writeBody(body, returnType, this.exchange).block(Duration.ofSeconds(5));
 
@@ -179,8 +168,7 @@ public class MessageWriterResultHandlerTests {
 	@Test  // SPR-13318
 	public void jacksonTypeWithSubTypeOfListElement() throws Exception {
 
-		MethodParameter returnType = on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(List.class, Identifiable.class));
+		MethodParameter returnType = on(TestController.class).resolveReturnType(List.class, Identifiable.class);
 
 		List<SimpleBean> body = Arrays.asList(new SimpleBean(123L, "foo"), new SimpleBean(456L, "bar"));
 		this.resultHandler.writeBody(body, returnType, this.exchange).block(Duration.ofSeconds(5));
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolverTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolverTests.java
index 43819df9b29..012c998fcdc 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolverTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolverTests.java
@@ -38,13 +38,16 @@ import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
 import org.springframework.web.bind.support.WebExchangeBindException;
-import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.method.ResolvableMethod;
+import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.adapter.DefaultServerWebExchange;
 
-import static org.junit.Assert.*;
-import static org.springframework.core.ResolvableType.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
 
 /**
  * Unit tests for {@link ModelAttributeMethodArgumentResolver}.
@@ -76,13 +79,13 @@ public class ModelAttributeMethodArgumentResolverTests {
 		MethodParameter param = this.testMethod.annotated(ModelAttribute.class).arg(Foo.class);
 		assertTrue(resolver.supportsParameter(param));
 
-		param = this.testMethod.annotated(ModelAttribute.class).arg(forClassWithGenerics(Mono.class, Foo.class));
+		param = this.testMethod.annotated(ModelAttribute.class).arg(Mono.class, Foo.class);
 		assertTrue(resolver.supportsParameter(param));
 
 		param = this.testMethod.notAnnotated(ModelAttribute.class).arg(Foo.class);
 		assertFalse(resolver.supportsParameter(param));
 
-		param = this.testMethod.notAnnotated(ModelAttribute.class).arg(forClassWithGenerics(Mono.class, Foo.class));
+		param = this.testMethod.notAnnotated(ModelAttribute.class).arg(Mono.class, Foo.class);
 		assertFalse(resolver.supportsParameter(param));
 	}
 
@@ -94,13 +97,13 @@ public class ModelAttributeMethodArgumentResolverTests {
 		MethodParameter param = this.testMethod.notAnnotated(ModelAttribute.class).arg(Foo.class);
 		assertTrue(resolver.supportsParameter(param));
 
-		param = this.testMethod.notAnnotated(ModelAttribute.class).arg(forClassWithGenerics(Mono.class, Foo.class));
+		param = this.testMethod.notAnnotated(ModelAttribute.class).arg(Mono.class, Foo.class);
 		assertTrue(resolver.supportsParameter(param));
 
 		param = this.testMethod.notAnnotated(ModelAttribute.class).arg(String.class);
 		assertFalse(resolver.supportsParameter(param));
 
-		param = this.testMethod.notAnnotated(ModelAttribute.class).arg(forClassWithGenerics(Mono.class, String.class));
+		param = this.testMethod.notAnnotated(ModelAttribute.class).arg(Mono.class, String.class);
 		assertFalse(resolver.supportsParameter(param));
 	}
 
@@ -115,8 +118,8 @@ public class ModelAttributeMethodArgumentResolverTests {
 	@Test
 	public void createAndBindToMono() throws Exception {
 
-		MethodParameter parameter = this.testMethod.notAnnotated(ModelAttribute.class)
-				.arg(forClassWithGenerics(Mono.class, Foo.class));
+		MethodParameter parameter = this.testMethod
+				.notAnnotated(ModelAttribute.class).arg(Mono.class, Foo.class);
 
 		testBindFoo(parameter, mono -> {
 			assertTrue(mono.getClass().getName(), mono instanceof Mono);
@@ -129,8 +132,8 @@ public class ModelAttributeMethodArgumentResolverTests {
 	@Test
 	public void createAndBindToSingle() throws Exception {
 
-		MethodParameter parameter = this.testMethod.annotated(ModelAttribute.class)
-				.arg(forClassWithGenerics(Single.class, Foo.class));
+		MethodParameter parameter = this.testMethod
+				.annotated(ModelAttribute.class).arg(Single.class, Foo.class);
 
 		testBindFoo(parameter, single -> {
 			assertTrue(single.getClass().getName(), single instanceof Single);
@@ -191,8 +194,8 @@ public class ModelAttributeMethodArgumentResolverTests {
 		foo.setName("Jim");
 		this.bindContext.getModel().addAttribute("foo", Mono.just(foo));
 
-		MethodParameter parameter = this.testMethod.notAnnotated(ModelAttribute.class)
-				.arg(forClassWithGenerics(Mono.class, Foo.class));
+		MethodParameter parameter = this.testMethod
+				.notAnnotated(ModelAttribute.class).arg(Mono.class, Foo.class);
 
 		testBindFoo(parameter, mono -> {
 			assertTrue(mono.getClass().getName(), mono instanceof Mono);
@@ -230,8 +233,8 @@ public class ModelAttributeMethodArgumentResolverTests {
 	@SuppressWarnings("unchecked")
 	public void validationErrorToMono() throws Exception {
 
-		MethodParameter parameter = this.testMethod.notAnnotated(ModelAttribute.class)
-				.arg(forClassWithGenerics(Mono.class, Foo.class));
+		MethodParameter parameter = this.testMethod
+				.notAnnotated(ModelAttribute.class).arg(Mono.class, Foo.class);
 
 		testValidationError(parameter,
 				resolvedArgumentMono -> {
@@ -246,8 +249,8 @@ public class ModelAttributeMethodArgumentResolverTests {
 	@SuppressWarnings("unchecked")
 	public void validationErrorToSingle() throws Exception {
 
-		MethodParameter parameter = this.testMethod.annotated(ModelAttribute.class)
-				.arg(forClassWithGenerics(Single.class, Foo.class));
+		MethodParameter parameter = this.testMethod
+				.annotated(ModelAttribute.class).arg(Single.class, Foo.class);
 
 		testValidationError(parameter,
 				resolvedArgumentMono -> {
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestBodyArgumentResolverTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestBodyArgumentResolverTests.java
index 0132ed889c4..057e1f435c9 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestBodyArgumentResolverTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestBodyArgumentResolverTests.java
@@ -33,15 +33,14 @@ import rx.RxReactiveStreams;
 import rx.Single;
 
 import org.springframework.core.MethodParameter;
-import org.springframework.core.ResolvableType;
 import org.springframework.core.codec.StringDecoder;
 import org.springframework.http.codec.DecoderHttpMessageReader;
 import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
 import org.springframework.web.bind.annotation.RequestBody;
-import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.method.ResolvableMethod;
+import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.ServerWebInputException;
 import org.springframework.web.server.adapter.DefaultServerWebExchange;
@@ -51,7 +50,6 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
-import static org.springframework.core.ResolvableType.forClassWithGenerics;
 
 /**
  * Unit tests for {@link RequestBodyArgumentResolver}. When adding a test also
@@ -77,13 +75,13 @@ public class RequestBodyArgumentResolverTests {
 
 	@Test
 	public void supports() throws Exception {
+		MethodParameter param;
 
-		ResolvableType type = forClassWithGenerics(Mono.class, String.class);
-		assertTrue(this.resolver.supportsParameter(
-				this.testMethod.annotated(RequestBody.class, required()).arg(type)));
+		param = this.testMethod.annotated(RequestBody.class, required()).arg(Mono.class, String.class);
+		assertTrue(this.resolver.supportsParameter(param));
 
-		MethodParameter parameter = this.testMethod.notAnnotated(RequestBody.class).arg(String.class);
-		assertFalse(this.resolver.supportsParameter(parameter));
+		param = this.testMethod.notAnnotated(RequestBody.class).arg(String.class);
+		assertFalse(this.resolver.supportsParameter(param));
 	}
 
 	@Test
@@ -112,15 +110,15 @@ public class RequestBodyArgumentResolverTests {
 	@Test
 	@SuppressWarnings("unchecked")
 	public void emptyBodyWithMono() throws Exception {
-		ResolvableType type = forClassWithGenerics(Mono.class, String.class);
+		MethodParameter param;
 
-		MethodParameter param = this.testMethod.annotated(RequestBody.class, required()).arg(type);
+		param = this.testMethod.annotated(RequestBody.class, required()).arg(Mono.class, String.class);
 		StepVerifier.create((Mono<Void>) resolveValueWithEmptyBody(param))
 				.expectNextCount(0)
 				.expectError(ServerWebInputException.class)
 				.verify();
 
-		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(type);
+		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(Mono.class, String.class);
 		StepVerifier.create((Mono<Void>) resolveValueWithEmptyBody(param))
 				.expectNextCount(0)
 				.expectComplete()
@@ -130,15 +128,15 @@ public class RequestBodyArgumentResolverTests {
 	@Test
 	@SuppressWarnings("unchecked")
 	public void emptyBodyWithFlux() throws Exception {
-		ResolvableType type = forClassWithGenerics(Flux.class, String.class);
+		MethodParameter param;
 
-		MethodParameter param = this.testMethod.annotated(RequestBody.class, required()).arg(type);
+		param = this.testMethod.annotated(RequestBody.class, required()).arg(Flux.class, String.class);
 		StepVerifier.create((Flux<Void>) resolveValueWithEmptyBody(param))
 				.expectNextCount(0)
 				.expectError(ServerWebInputException.class)
 				.verify();
 
-		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(type);
+		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(Flux.class, String.class);
 		StepVerifier.create((Flux<Void>) resolveValueWithEmptyBody(param))
 				.expectNextCount(0)
 				.expectComplete()
@@ -147,16 +145,16 @@ public class RequestBodyArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithSingle() throws Exception {
-		ResolvableType type = forClassWithGenerics(Single.class, String.class);
+		MethodParameter param;
 
-		MethodParameter param = this.testMethod.annotated(RequestBody.class, required()).arg(type);
+		param = this.testMethod.annotated(RequestBody.class, required()).arg(Single.class, String.class);
 		Single<String> single = resolveValueWithEmptyBody(param);
 		StepVerifier.create(RxReactiveStreams.toPublisher(single))
 				.expectNextCount(0)
 				.expectError(ServerWebInputException.class)
 				.verify();
 
-		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(type);
+		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(Single.class, String.class);
 		single = resolveValueWithEmptyBody(param);
 		StepVerifier.create(RxReactiveStreams.toPublisher(single))
 				.expectNextCount(0)
@@ -166,16 +164,16 @@ public class RequestBodyArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithMaybe() throws Exception {
-		ResolvableType type = forClassWithGenerics(Maybe.class, String.class);
+		MethodParameter param;
 
-		MethodParameter param = this.testMethod.annotated(RequestBody.class, required()).arg(type);
+		param = this.testMethod.annotated(RequestBody.class, required()).arg(Maybe.class, String.class);
 		Maybe<String> maybe = resolveValueWithEmptyBody(param);
 		StepVerifier.create(maybe.toFlowable())
 				.expectNextCount(0)
 				.expectError(ServerWebInputException.class)
 				.verify();
 
-		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(type);
+		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(Maybe.class, String.class);
 		maybe = resolveValueWithEmptyBody(param);
 		StepVerifier.create(maybe.toFlowable())
 				.expectNextCount(0)
@@ -185,16 +183,19 @@ public class RequestBodyArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithObservable() throws Exception {
-		ResolvableType type = forClassWithGenerics(Observable.class, String.class);
 
-		MethodParameter param = this.testMethod.annotated(RequestBody.class, required()).arg(type);
+		MethodParameter param = this.testMethod
+				.annotated(RequestBody.class, required()).arg(Observable.class, String.class);
+
 		Observable<String> observable = resolveValueWithEmptyBody(param);
 		StepVerifier.create(RxReactiveStreams.toPublisher(observable))
 				.expectNextCount(0)
 				.expectError(ServerWebInputException.class)
 				.verify();
 
-		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(type);
+		param = this.testMethod
+				.annotated(RequestBody.class, notRequired()).arg(Observable.class, String.class);
+
 		observable = resolveValueWithEmptyBody(param);
 		StepVerifier.create(RxReactiveStreams.toPublisher(observable))
 				.expectNextCount(0)
@@ -204,16 +205,19 @@ public class RequestBodyArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithCompletableFuture() throws Exception {
-		ResolvableType type = forClassWithGenerics(CompletableFuture.class, String.class);
 
-		MethodParameter param = this.testMethod.annotated(RequestBody.class, required()).arg(type);
+		MethodParameter param = this.testMethod
+				.annotated(RequestBody.class, required()).arg(CompletableFuture.class, String.class);
+
 		CompletableFuture<String> future = resolveValueWithEmptyBody(param);
 		future.whenComplete((text, ex) -> {
 			assertNull(text);
 			assertNotNull(ex);
 		});
 
-		param = this.testMethod.annotated(RequestBody.class, notRequired()).arg(type);
+		param = this.testMethod
+				.annotated(RequestBody.class, notRequired()).arg(CompletableFuture.class, String.class);
+
 		future = resolveValueWithEmptyBody(param);
 		future.whenComplete((text, ex) -> {
 			assertNotNull(text);
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestParamMethodArgumentResolverTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestParamMethodArgumentResolverTests.java
index c47b8a44ef0..aef2be9dec3 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestParamMethodArgumentResolverTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/RequestParamMethodArgumentResolverTests.java
@@ -26,7 +26,6 @@ import org.junit.Test;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
 import org.springframework.core.MethodParameter;
 import org.springframework.format.support.DefaultFormattingConversionService;
 import org.springframework.http.MediaType;
@@ -145,7 +144,6 @@ public class RequestParamMethodArgumentResolverTests {
 	public void resolveSimpleTypeParam() throws Exception {
 		ServerWebExchange exchange = exchangeWithQuery("stringNotAnnot=plainValue");
 		MethodParameter param = this.testMethod.notAnnotated(RequestParam.class).arg(String.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 		Object result = resolve(param, exchange);
 		assertEquals("plainValue", result);
 	}
@@ -153,7 +151,6 @@ public class RequestParamMethodArgumentResolverTests {
 	@Test  // SPR-8561
 	public void resolveSimpleTypeParamToNull() throws Exception {
 		MethodParameter param = this.testMethod.notAnnotated(RequestParam.class).arg(String.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 		assertNull(resolve(param, exchange()));
 	}
 
@@ -168,7 +165,6 @@ public class RequestParamMethodArgumentResolverTests {
 	@Test
 	public void resolveEmptyValueWithoutDefault() throws Exception {
 		MethodParameter param = this.testMethod.notAnnotated(RequestParam.class).arg(String.class);
-		param.initParameterNameDiscovery(new LocalVariableTableParameterNameDiscoverer());
 		assertEquals("", resolve(param, exchangeWithQuery("stringNotAnnot=")));
 	}
 
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityResultHandlerTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityResultHandlerTests.java
index 60adbcad33b..8281297b65d 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityResultHandlerTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityResultHandlerTests.java
@@ -61,7 +61,6 @@ import org.springframework.web.server.adapter.DefaultServerWebExchange;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
-import static org.springframework.core.ResolvableType.forClass;
 import static org.springframework.core.ResolvableType.forClassWithGenerics;
 import static org.springframework.http.ResponseEntity.notFound;
 import static org.springframework.http.ResponseEntity.ok;
@@ -124,13 +123,13 @@ public class ResponseEntityResultHandlerTests {
 		MethodParameter returnType = on(TestController.class).resolveReturnType(entity(String.class));
 		assertTrue(this.resultHandler.supports(handlerResult(value, returnType)));
 
-		returnType = on(TestController.class).resolveReturnType(asyncEntity(Mono.class, String.class));
+		returnType = on(TestController.class).resolveReturnType(Mono.class, entity(String.class));
 		assertTrue(this.resultHandler.supports(handlerResult(value, returnType)));
 
-		returnType = on(TestController.class).resolveReturnType(asyncEntity(Single.class, String.class));
+		returnType = on(TestController.class).resolveReturnType(Single.class, entity(String.class));
 		assertTrue(this.resultHandler.supports(handlerResult(value, returnType)));
 
-		returnType = on(TestController.class).resolveReturnType(asyncEntity(CompletableFuture.class, String.class));
+		returnType = on(TestController.class).resolveReturnType(CompletableFuture.class, entity(String.class));
 		assertTrue(this.resultHandler.supports(handlerResult(value, returnType)));
 	}
 
@@ -140,10 +139,10 @@ public class ResponseEntityResultHandlerTests {
 
 		Object value = null;
 
-		MethodParameter returnType = on(TestController.class).resolveReturnType(forClass(String.class));
+		MethodParameter returnType = on(TestController.class).resolveReturnType(String.class);
 		assertFalse(this.resultHandler.supports(handlerResult(value, returnType)));
 
-		returnType = on(TestController.class).resolveReturnType(forClass(Completable.class));
+		returnType = on(TestController.class).resolveReturnType(Completable.class);
 		assertFalse(this.resultHandler.supports(handlerResult(value, returnType)));
 	}
 
@@ -181,7 +180,7 @@ public class ResponseEntityResultHandlerTests {
 	@Test
 	public void handleResponseEntityWithNullBody() throws Exception {
 		Object returnValue = Mono.just(notFound().build());
-		MethodParameter type = on(TestController.class).resolveReturnType(asyncEntity(Mono.class, String.class));
+		MethodParameter type = on(TestController.class).resolveReturnType(Mono.class, entity(String.class));
 		HandlerResult result = handlerResult(returnValue, type);
 		this.resultHandler.handleResult(createExchange(), result).block(Duration.ofSeconds(5));
 
@@ -196,15 +195,15 @@ public class ResponseEntityResultHandlerTests {
 		testHandle(returnValue, returnType);
 
 		returnValue = Mono.just(ok("abc"));
-		returnType = on(TestController.class).resolveReturnType(asyncEntity(Mono.class, String.class));
+		returnType = on(TestController.class).resolveReturnType(Mono.class, entity(String.class));
 		testHandle(returnValue, returnType);
 
 		returnValue = Mono.just(ok("abc"));
-		returnType = on(TestController.class).resolveReturnType(asyncEntity(Single.class, String.class));
+		returnType = on(TestController.class).resolveReturnType(Single.class, entity(String.class));
 		testHandle(returnValue, returnType);
 
 		returnValue = Mono.just(ok("abc"));
-		returnType = on(TestController.class).resolveReturnType(asyncEntity(CompletableFuture.class, String.class));
+		returnType = on(TestController.class).resolveReturnType(CompletableFuture.class, entity(String.class));
 		testHandle(returnValue, returnType);
 	}
 
@@ -296,8 +295,8 @@ public class ResponseEntityResultHandlerTests {
 		exchange.getAttributes().put(HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE,
 				Collections.singleton(MediaType.APPLICATION_JSON));
 
-		HandlerResult result = new HandlerResult(new TestController(), Mono.just(ok().body("body")),
-				on(TestController.class).resolveReturnType(forClassWithGenerics(Mono.class, ResponseEntity.class)));
+		MethodParameter type = on(TestController.class).resolveReturnType(Mono.class, ResponseEntity.class);
+		HandlerResult result = new HandlerResult(new TestController(), Mono.just(ok().body("body")), type);
 
 		this.resultHandler.handleResult(exchange, result).block(Duration.ofSeconds(5));
 
@@ -312,8 +311,7 @@ public class ResponseEntityResultHandlerTests {
 		exchange.getAttributes().put(HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE,
 				Collections.singleton(MediaType.APPLICATION_JSON));
 
-		MethodParameter returnType = on(TestController.class).resolveReturnType(forClassWithGenerics(Mono.class, ResponseEntity.class));
-
+		MethodParameter returnType = on(TestController.class).resolveReturnType(Mono.class, ResponseEntity.class);
 		HandlerResult result = new HandlerResult(new TestController(), Mono.just(notFound().build()), returnType);
 
 		this.resultHandler.handleResult(exchange, result).block(Duration.ofSeconds(5));
@@ -339,11 +337,7 @@ public class ResponseEntityResultHandlerTests {
 	}
 
 	private ResolvableType entity(Class<?> bodyType) {
-		return forClassWithGenerics(ResponseEntity.class, forClass(bodyType));
-	}
-
-	private ResolvableType asyncEntity(Class<?> asyncType, Class<?> bodyType) {
-		return forClassWithGenerics(asyncType, entity(bodyType));
+		return forClassWithGenerics(ResponseEntity.class, bodyType);
 	}
 
 	private HandlerResult handlerResult(Object returnValue, MethodParameter returnType) {
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandlerTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandlerTests.java
index 373191ac7b2..d42ce6162b2 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandlerTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandlerTests.java
@@ -62,7 +62,6 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.springframework.core.ResolvableType.forClass;
-import static org.springframework.core.ResolvableType.forClassWithGenerics;
 import static org.springframework.http.MediaType.APPLICATION_JSON;
 import static org.springframework.web.method.ResolvableMethod.on;
 
@@ -90,11 +89,11 @@ public class ViewResolutionResultHandlerTests {
 
 		testSupports(on(TestController.class).resolveReturnType(String.class));
 		testSupports(on(TestController.class).resolveReturnType(View.class));
-		testSupports(on(TestController.class).resolveReturnType(forClassWithGenerics(Mono.class, String.class)));
-		testSupports(on(TestController.class).resolveReturnType(forClassWithGenerics(Mono.class, View.class)));
-		testSupports(on(TestController.class).resolveReturnType(forClassWithGenerics(Single.class, String.class)));
-		testSupports(on(TestController.class).resolveReturnType(forClassWithGenerics(Single.class, View.class)));
-		testSupports(on(TestController.class).resolveReturnType(forClassWithGenerics(Mono.class, Void.class)));
+		testSupports(on(TestController.class).resolveReturnType(Mono.class, String.class));
+		testSupports(on(TestController.class).resolveReturnType(Mono.class, View.class));
+		testSupports(on(TestController.class).resolveReturnType(Single.class, String.class));
+		testSupports(on(TestController.class).resolveReturnType(Single.class, View.class));
+		testSupports(on(TestController.class).resolveReturnType(Mono.class, Void.class));
 		testSupports(on(TestController.class).resolveReturnType(Completable.class));
 		testSupports(on(TestController.class).resolveReturnType(Model.class));
 		testSupports(on(TestController.class).resolveReturnType(Map.class));
@@ -139,27 +138,27 @@ public class ViewResolutionResultHandlerTests {
 		returnValue = new TestView("account");
 		testHandle("/path", returnType, returnValue, "account: {id=123}");
 
-		returnType = on(TestController.class).resolveReturnType(forClassWithGenerics(Mono.class, View.class));
+		returnType = on(TestController.class).resolveReturnType(Mono.class, View.class);
 		returnValue = Mono.just(new TestView("account"));
 		testHandle("/path", returnType, returnValue, "account: {id=123}");
 
-		returnType = on(TestController.class).resolveReturnType(forClass(String.class));
+		returnType = on(TestController.class).resolveReturnType(String.class);
 		returnValue = "account";
 		testHandle("/path", returnType, returnValue, "account: {id=123}", resolver);
 
-		returnType = on(TestController.class).resolveReturnType(forClassWithGenerics(Mono.class, String.class));
+		returnType = on(TestController.class).resolveReturnType(Mono.class, String.class);
 		returnValue = Mono.just("account");
 		testHandle("/path", returnType, returnValue, "account: {id=123}", resolver);
 
-		returnType = on(TestController.class).resolveReturnType(forClass(Model.class));
+		returnType = on(TestController.class).resolveReturnType(Model.class);
 		returnValue = new ConcurrentModel().addAttribute("name", "Joe");
 		testHandle("/account", returnType, returnValue, "account: {id=123, name=Joe}", resolver);
 
-		returnType = on(TestController.class).resolveReturnType(forClass(Map.class));
+		returnType = on(TestController.class).resolveReturnType(Map.class);
 		returnValue = Collections.singletonMap("name", "Joe");
 		testHandle("/account", returnType, returnValue, "account: {id=123, name=Joe}", resolver);
 
-		returnType = on(TestController.class).resolveReturnType(forClass(TestBean.class));
+		returnType = on(TestController.class).resolveReturnType(TestBean.class);
 		returnValue = new TestBean("Joe");
 		String responseBody = "account: {" +
 				"id=123, " +
@@ -184,17 +183,10 @@ public class ViewResolutionResultHandlerTests {
 
 	@Test
 	public void defaultViewName() throws Exception {
-
 		testDefaultViewName(null, on(TestController.class).resolveReturnType(String.class));
-
-		testDefaultViewName(Mono.empty(), on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(Mono.class, String.class)));
-
-		testDefaultViewName(Mono.empty(), on(TestController.class)
-				.resolveReturnType(forClassWithGenerics(Mono.class, Void.class)));
-
-		testDefaultViewName(Completable.complete(), on(TestController.class)
-				.resolveReturnType(forClass(Completable.class)));
+		testDefaultViewName(Mono.empty(), on(TestController.class).resolveReturnType(Mono.class, String.class));
+		testDefaultViewName(Mono.empty(), on(TestController.class).resolveReturnType(Mono.class, Void.class));
+		testDefaultViewName(Completable.complete(), on(TestController.class).resolveReturnType(Completable.class));
 	}
 
 	private void testDefaultViewName(Object returnValue, MethodParameter returnType) throws URISyntaxException {