Apply "instanceof pattern matching" Eclipse clean-up in spring-core

This commit also applies additional clean-up tasks such as the following.

- final fields
- diamond operator (<>) for anonymous inner classes

This has only been applied to `src/main/java`.

spring-core/src/main/java/org/springframework/core/CollectionFactory.java

@@ -119,22 +119,21 @@ public static boolean isApproximableCollectionType(@Nullable Class<?> collection
 	 * @see java.util.TreeSet
 	 * @see java.util.LinkedHashSet
 	 */
-	@SuppressWarnings({"rawtypes", "unchecked", "cast"})
+	@SuppressWarnings({"rawtypes", "unchecked"})
 	public static <E> Collection<E> createApproximateCollection(@Nullable Object collection, int capacity) {
 		if (collection instanceof LinkedList) {
 			return new LinkedList<>();
 		}
 		else if (collection instanceof List) {
 			return new ArrayList<>(capacity);
 		}
-		else if (collection instanceof EnumSet) {
-			// Cast is necessary for compilation in Eclipse 4.4.1.
-			Collection<E> enumSet = (Collection<E>) EnumSet.copyOf((EnumSet) collection);
-			enumSet.clear();
-			return enumSet;
+		else if (collection instanceof EnumSet enumSet) {
+			Collection<E> copy = EnumSet.copyOf(enumSet);
+			copy.clear();
+			return copy;
 		}
-		else if (collection instanceof SortedSet) {
-			return new TreeSet<>(((SortedSet<E>) collection).comparator());
+		else if (collection instanceof SortedSet sortedSet) {
+			return new TreeSet<>(sortedSet.comparator());
 		}
 		else {
 			return new LinkedHashSet<>(capacity);
@@ -178,7 +177,7 @@ public static <E> Collection<E> createCollection(Class<?> collectionType, int ca
 	 * @see java.util.TreeSet
 	 * @see java.util.EnumSet
 	 */
-	@SuppressWarnings({"unchecked", "cast"})
+	@SuppressWarnings("unchecked")
 	public static <E> Collection<E> createCollection(Class<?> collectionType, @Nullable Class<?> elementType, int capacity) {
 		Assert.notNull(collectionType, "Collection type must not be null");
 		if (collectionType.isInterface()) {
@@ -197,8 +196,7 @@ else if (SortedSet.class == collectionType || NavigableSet.class == collectionTy
 		}
 		else if (EnumSet.class.isAssignableFrom(collectionType)) {
 			Assert.notNull(elementType, "Cannot create EnumSet for unknown element type");
-			// Cast is necessary for compilation in Eclipse 4.4.1.
-			return (Collection<E>) EnumSet.noneOf(asEnumType(elementType));
+			return EnumSet.noneOf(asEnumType(elementType));
 		}
 		else {
 			if (!Collection.class.isAssignableFrom(collectionType)) {
@@ -243,13 +241,13 @@ public static boolean isApproximableMapType(@Nullable Class<?> mapType) {
 	 */
 	@SuppressWarnings({"rawtypes", "unchecked"})
 	public static <K, V> Map<K, V> createApproximateMap(@Nullable Object map, int capacity) {
-		if (map instanceof EnumMap) {
-			EnumMap enumMap = new EnumMap((EnumMap) map);
-			enumMap.clear();
-			return enumMap;
+		if (map instanceof EnumMap enumMap) {
+			EnumMap copy = new EnumMap(enumMap);
+			copy.clear();
+			return copy;
 		}
-		else if (map instanceof SortedMap) {
-			return new TreeMap<>(((SortedMap<K, V>) map).comparator());
+		else if (map instanceof SortedMap sortedMap) {
+			return new TreeMap<>(sortedMap.comparator());
 		}
 		else {
 			return new LinkedHashMap<>(capacity);

spring-core/src/main/java/org/springframework/core/MethodClassKey.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -54,10 +54,9 @@ public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof MethodClassKey)) {
+		if (!(other instanceof MethodClassKey otherKey)) {
 			return false;
 		}
-		MethodClassKey otherKey = (MethodClassKey) other;
 		return (this.method.equals(otherKey.method) &&
 				ObjectUtils.nullSafeEquals(this.targetClass, otherKey.targetClass));
 	}

spring-core/src/main/java/org/springframework/core/MethodParameter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -753,10 +753,9 @@ public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof MethodParameter)) {
+		if (!(other instanceof MethodParameter otherParam)) {
 			return false;
 		}
-		MethodParameter otherParam = (MethodParameter) other;
 		return (getContainingClass() == otherParam.getContainingClass() &&
 				ObjectUtils.nullSafeEquals(this.typeIndexesPerLevel, otherParam.typeIndexesPerLevel) &&
 				this.nestingLevel == otherParam.nestingLevel &&

spring-core/src/main/java/org/springframework/core/ParameterizedTypeReference.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -92,7 +92,7 @@ public String toString() {
 	 * @since 4.3.12
 	 */
 	public static <T> ParameterizedTypeReference<T> forType(Type type) {
-		return new ParameterizedTypeReference<T>(type) {
+		return new ParameterizedTypeReference<>(type) {
 		};
 	}
 

spring-core/src/main/java/org/springframework/core/ResolvableType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -594,8 +594,7 @@ private boolean isUnresolvableTypeVariable() {
 	 * without specific bounds (i.e., equal to {@code ? extends Object}).
 	 */
 	private boolean isWildcardWithoutBounds() {
-		if (this.type instanceof WildcardType) {
-			WildcardType wt = (WildcardType) this.type;
+		if (this.type instanceof WildcardType wt) {
 			if (wt.getLowerBounds().length == 0) {
 				Type[] upperBounds = wt.getUpperBounds();
 				if (upperBounds.length == 0 || (upperBounds.length == 1 && Object.class == upperBounds[0])) {
@@ -870,8 +869,7 @@ private ResolvableType resolveVariable(TypeVariable<?> variable) {
 		if (this.type instanceof TypeVariable) {
 			return resolveType().resolveVariable(variable);
 		}
-		if (this.type instanceof ParameterizedType) {
-			ParameterizedType parameterizedType = (ParameterizedType) this.type;
+		if (this.type instanceof ParameterizedType parameterizedType) {
 			Class<?> resolved = resolve();
 			if (resolved == null) {
 				return null;
@@ -906,11 +904,10 @@ public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof ResolvableType)) {
+		if (!(other instanceof ResolvableType otherType)) {
 			return false;
 		}
 
-		ResolvableType otherType = (ResolvableType) other;
 		if (!ObjectUtils.nullSafeEquals(this.type, otherType.type)) {
 			return false;
 		}
@@ -1573,10 +1570,9 @@ public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}
-			if (!(other instanceof ParameterizedType)) {
+			if (!(other instanceof ParameterizedType otherType)) {
 				return false;
 			}
-			ParameterizedType otherType = (ParameterizedType) other;
 			return (otherType.getOwnerType() == null && this.rawType.equals(otherType.getRawType()) &&
 					Arrays.equals(this.typeArguments, otherType.getActualTypeArguments()));
 		}

spring-core/src/main/java/org/springframework/core/annotation/AnnotationUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -1006,12 +1006,10 @@ private static Object adaptValue(
 				return names;
 			}
 		}
-		if (value instanceof Annotation) {
-			Annotation annotation = (Annotation) value;
+		if (value instanceof Annotation annotation) {
 			return MergedAnnotation.from(annotatedElement, annotation).synthesize();
 		}
-		if (value instanceof Annotation[]) {
-			Annotation[] annotations = (Annotation[]) value;
+		if (value instanceof Annotation[] annotations) {
 			Annotation[] synthesized = (Annotation[]) Array.newInstance(
 					annotations.getClass().getComponentType(), annotations.length);
 			for (int i = 0; i < annotations.length; i++) {

spring-core/src/main/java/org/springframework/core/annotation/AnnotationsScanner.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -521,8 +521,7 @@ private static boolean isWithoutHierarchy(AnnotatedElement source, SearchStrateg
 			return (searchStrategy == SearchStrategy.TYPE_HIERARCHY_AND_ENCLOSING_CLASSES ? noSuperTypes &&
 					sourceClass.getEnclosingClass() == null : noSuperTypes);
 		}
-		if (source instanceof Method) {
-			Method sourceMethod = (Method) source;
+		if (source instanceof Method sourceMethod) {
 			return (Modifier.isPrivate(sourceMethod.getModifiers()) ||
 					isWithoutHierarchy(sourceMethod.getDeclaringClass(), searchStrategy));
 		}

spring-core/src/main/java/org/springframework/core/annotation/MergedAnnotationsCollection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -221,7 +221,7 @@ static MergedAnnotations of(Collection<MergedAnnotation<?>> annotations) {
 	private class AnnotationsSpliterator<A extends Annotation> implements Spliterator<MergedAnnotation<A>> {
 
 		@Nullable
-		private Object requiredType;
+		private final Object requiredType;
 
 		private final int[] mappingCursors;
 

spring-core/src/main/java/org/springframework/core/annotation/TypeMappedAnnotation.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -439,8 +439,7 @@ else if (value instanceof Class[] && type == String[].class) {
 			}
 			value = names;
 		}
-		else if (value instanceof String[] && type == Class[].class) {
-			String[] names = (String[]) value;
+		else if (value instanceof String[] names && type == Class[].class) {
 			Class<?>[] classes = new Class<?>[names.length];
 			for (int i = 0; i < names.length; i++) {
 				classes[i] = ClassUtils.resolveClassName(names[i], getClassLoader());

spring-core/src/main/java/org/springframework/core/convert/Property.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -263,10 +263,9 @@ public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof Property)) {
+		if (!(other instanceof Property otherProperty)) {
 			return false;
 		}
-		Property otherProperty = (Property) other;
 		return (ObjectUtils.nullSafeEquals(this.objectType, otherProperty.objectType) &&
 				ObjectUtils.nullSafeEquals(this.name, otherProperty.name) &&
 				ObjectUtils.nullSafeEquals(this.readMethod, otherProperty.readMethod) &&

spring-core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -458,10 +458,9 @@ public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof TypeDescriptor)) {
+		if (!(other instanceof TypeDescriptor otherDesc)) {
 			return false;
 		}
-		TypeDescriptor otherDesc = (TypeDescriptor) other;
 		if (getType() != otherDesc.getType()) {
 			return false;
 		}

spring-core/src/main/java/org/springframework/core/convert/support/ByteBufferConverter.java

@@ -88,8 +88,7 @@ private boolean matchesToByteBuffer(TypeDescriptor sourceType) {
 	@Nullable
 	public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
 		boolean byteBufferTarget = targetType.isAssignableTo(BYTE_BUFFER_TYPE);
-		if (source instanceof ByteBuffer) {
-			ByteBuffer buffer = (ByteBuffer) source;
+		if (source instanceof ByteBuffer buffer) {
 			return (byteBufferTarget ? buffer.duplicate() : convertFromByteBuffer(buffer, targetType));
 		}
 		if (byteBufferTarget) {

spring-core/src/main/java/org/springframework/core/convert/support/GenericConversionService.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -463,10 +463,9 @@ public boolean equals(@Nullable Object other) {
 			if (this == other) {
 				return true;
 			}
-			if (!(other instanceof ConverterCacheKey)) {
+			if (!(other instanceof ConverterCacheKey otherKey)) {
 				return false;
 			}
-			ConverterCacheKey otherKey = (ConverterCacheKey) other;
 			return (this.sourceType.equals(otherKey.sourceType)) &&
 					this.targetType.equals(otherKey.targetType);
 		}

spring-core/src/main/java/org/springframework/core/convert/support/ObjectToObjectConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -92,8 +92,7 @@ public Object convert(@Nullable Object source, TypeDescriptor sourceType, TypeDe
 		Member member = getValidatedMember(targetClass, sourceClass);
 
 		try {
-			if (member instanceof Method) {
-				Method method = (Method) member;
+			if (member instanceof Method method) {
 				ReflectionUtils.makeAccessible(method);
 				if (!Modifier.isStatic(method.getModifiers())) {
 					return method.invoke(source);
@@ -152,8 +151,7 @@ private static Member getValidatedMember(Class<?> targetClass, Class<?> sourceCl
 	}
 
 	private static boolean isApplicable(Member member, Class<?> sourceClass) {
-		if (member instanceof Method) {
-			Method method = (Method) member;
+		if (member instanceof Method method) {
 			return (!Modifier.isStatic(method.getModifiers()) ?
 					ClassUtils.isAssignable(method.getDeclaringClass(), sourceClass) :
 					method.getParameterTypes()[0] == sourceClass);

spring-core/src/main/java/org/springframework/core/io/AbstractFileResolvingResource.java

@@ -106,8 +106,7 @@ boolean checkReadable(URL url) {
 				// Try InputStream resolution for jar resources
 				URLConnection con = url.openConnection();
 				customizeConnection(con);
-				if (con instanceof HttpURLConnection) {
-					HttpURLConnection httpCon = (HttpURLConnection) con;
+				if (con instanceof HttpURLConnection httpCon) {
 					int code = httpCon.getResponseCode();
 					if (code != HttpURLConnection.HTTP_OK) {
 						httpCon.disconnect();

spring-core/src/main/java/org/springframework/core/io/ClassPathResource.java

@@ -267,10 +267,9 @@ public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof ClassPathResource)) {
+		if (!(other instanceof ClassPathResource otherRes)) {
 			return false;
 		}
-		ClassPathResource otherRes = (ClassPathResource) other;
 		return (this.path.equals(otherRes.path) &&
 				ObjectUtils.nullSafeEquals(this.classLoader, otherRes.classLoader) &&
 				ObjectUtils.nullSafeEquals(this.clazz, otherRes.clazz));

spring-core/src/main/java/org/springframework/core/io/buffer/DataBufferUtils.java

@@ -513,8 +513,7 @@ public static <T extends DataBuffer> T touch(T dataBuffer, Object hint) {
 	 * @return {@code true} if the buffer was released; {@code false} otherwise.
 	 */
 	public static boolean release(@Nullable DataBuffer dataBuffer) {
-		if (dataBuffer instanceof PooledDataBuffer) {
-			PooledDataBuffer pooledDataBuffer = (PooledDataBuffer) dataBuffer;
+		if (dataBuffer instanceof PooledDataBuffer pooledDataBuffer) {
 			if (pooledDataBuffer.isAllocated()) {
 				try {
 					return pooledDataBuffer.release();

spring-core/src/main/java/org/springframework/core/io/buffer/DefaultDataBuffer.java

@@ -431,10 +431,9 @@ public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof DefaultDataBuffer)) {
+		if (!(other instanceof DefaultDataBuffer otherBuffer)) {
 			return false;
 		}
-		DefaultDataBuffer otherBuffer = (DefaultDataBuffer) other;
 		return (this.readPosition == otherBuffer.readPosition &&
 				this.writePosition == otherBuffer.writePosition &&
 				this.byteBuffer.equals(otherBuffer.byteBuffer));

spring-core/src/main/java/org/springframework/core/io/support/EncodedResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -165,10 +165,9 @@ public boolean equals(@Nullable Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof EncodedResource)) {
+		if (!(other instanceof EncodedResource otherResource)) {
 			return false;
 		}
-		EncodedResource otherResource = (EncodedResource) other;
 		return (this.resource.equals(otherResource.resource) &&
 				ObjectUtils.nullSafeEquals(this.charset, otherResource.charset) &&
 				ObjectUtils.nullSafeEquals(this.encoding, otherResource.encoding));