Merge branch '5.2.x'

spring-beans/src/main/java/org/springframework/beans/factory/config/YamlProcessor.java

@@ -432,8 +432,7 @@ public abstract class YamlProcessor {
 	/**
 	 * {@link Constructor} that supports filtering of unsupported types.
 	 * <p>If an unsupported type is encountered in a YAML document, an
-	 * {@link IllegalStateException} will be thrown from {@link #getClassForName(String)}.
+	 * {@link IllegalStateException} will be thrown from {@link #getClassForName}.
-	 * @since 5.1.16
 	 */
 	private class FilteringConstructor extends Constructor {
 
@@ -441,7 +440,6 @@ public abstract class YamlProcessor {
 			super(loaderOptions);
 		}
 
-
 		@Override
 		protected Class<?> getClassForName(String name) throws ClassNotFoundException {
 			Assert.state(YamlProcessor.this.supportedTypes.contains(name),

spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -79,6 +79,7 @@ import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
 import org.springframework.core.io.support.ResourcePatternResolver;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.ReflectionUtils;
 
@@ -836,7 +837,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 		// Publish early application events now that we finally have a multicaster...
 		Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
 		this.earlyApplicationEvents = null;
-		if (earlyEventsToProcess != null) {
+		if (!CollectionUtils.isEmpty(earlyEventsToProcess)) {
 			for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
 				getApplicationEventMulticaster().multicastEvent(earlyEvent);
 			}

spring-core/src/main/java/org/springframework/core/env/AbstractPropertyResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -223,6 +223,9 @@ public abstract class AbstractPropertyResolver implements ConfigurablePropertyRe
 	 * @see #setIgnoreUnresolvableNestedPlaceholders
 	 */
 	protected String resolveNestedPlaceholders(String value) {
+		if (value.isEmpty()) {
+			return value;
+		}
 		return (this.ignoreUnresolvableNestedPlaceholders ?
 				resolvePlaceholders(value) : resolveRequiredPlaceholders(value));
 	}

spring-core/src/main/java/org/springframework/core/env/EnumerablePropertySource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -44,10 +44,20 @@ import org.springframework.util.ObjectUtils;
  */
 public abstract class EnumerablePropertySource<T> extends PropertySource<T> {
 
+	/**
+	 * Create a new {@code EnumerablePropertySource} with the given name and source object.
+	 * @param name the associated name
+	 * @param source the source object
+	 */
 	public EnumerablePropertySource(String name, T source) {
 		super(name, source);
 	}
 
+	/**
+	 * Create a new {@code EnumerablePropertySource} with the given name and with a new
+	 * {@code Object} instance as the underlying source.
+	 * @param name the associated name
+	 */
 	protected EnumerablePropertySource(String name) {
 		super(name);
 	}

spring-core/src/main/java/org/springframework/core/env/MapPropertySource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -23,6 +23,8 @@ import org.springframework.util.StringUtils;
 
 /**
  * {@link PropertySource} that reads keys and values from a {@code Map} object.
+ * The underlying map should not contain any {@code null} values in order to
+ * comply with {@link #getProperty} and {@link #containsProperty} semantics.
  *
  * @author Chris Beams
  * @author Juergen Hoeller
@@ -31,6 +33,12 @@ import org.springframework.util.StringUtils;
  */
 public class MapPropertySource extends EnumerablePropertySource<Map<String, Object>> {
 
+	/**
+	 * Create a new {@code MapPropertySource} with the given name and {@code Map}.
+	 * @param name the associated name
+	 * @param source the Map source (without {@code null} values in order to get
+	 * consistent {@link #getProperty} and {@link #containsProperty} behavior)
+	 */
 	public MapPropertySource(String name, Map<String, Object> source) {
 		super(name, source);
 	}

spring-core/src/main/java/org/springframework/core/env/PropertyResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -98,7 +98,6 @@ public interface PropertyResolver {
 	 * @return the resolved String (never {@code null})
 	 * @throws IllegalArgumentException if given text is {@code null}
 	 * @see #resolveRequiredPlaceholders
-	 * @see org.springframework.util.SystemPropertyUtils#resolvePlaceholders(String)
 	 */
 	String resolvePlaceholders(String text);
 
@@ -109,7 +108,6 @@ public interface PropertyResolver {
 	 * @return the resolved String (never {@code null})
 	 * @throws IllegalArgumentException if given text is {@code null}
 	 * or if any placeholders are unresolvable
-	 * @see org.springframework.util.SystemPropertyUtils#resolvePlaceholders(String, boolean)
 	 */
 	String resolveRequiredPlaceholders(String text) throws IllegalArgumentException;
 

spring-core/src/main/java/org/springframework/core/env/PropertySource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -68,6 +68,8 @@ public abstract class PropertySource<T> {
 
 	/**
 	 * Create a new {@code PropertySource} with the given name and source object.
+	 * @param name the associated name
+	 * @param source the source object
 	 */
 	public PropertySource(String name, T source) {
 		Assert.hasText(name, "Property source name must contain at least one character");

spring-core/src/main/java/org/springframework/util/CollectionUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -16,7 +16,6 @@
 
 package org.springframework.util;
 
-import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -24,7 +23,6 @@ import java.util.Collections;
 import java.util.Enumeration;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
@@ -412,25 +410,28 @@ public abstract class CollectionUtils {
 
 	/**
 	 * Adapt a {@code Map<K, List<V>>} to an {@code MultiValueMap<K, V>}.
-	 * @param map the original map
+	 * @param targetMap the original map
-	 * @return the multi-value map
+	 * @return the adapted multi-value map (wrapping the original map)
 	 * @since 3.1
 	 */
-	public static <K, V> MultiValueMap<K, V> toMultiValueMap(Map<K, List<V>> map) {
+	public static <K, V> MultiValueMap<K, V> toMultiValueMap(Map<K, List<V>> targetMap) {
-		return new MultiValueMapAdapter<>(map);
+		Assert.notNull(targetMap, "'targetMap' must not be null");
+		return new MultiValueMapAdapter<>(targetMap);
 	}
 
 	/**
 	 * Return an unmodifiable view of the specified multi-value map.
-	 * @param  map the map for which an unmodifiable view is to be returned.
+	 * @param targetMap the map for which an unmodifiable view is to be returned.
-	 * @return an unmodifiable view of the specified multi-value map.
+	 * @return an unmodifiable view of the specified multi-value map
 	 * @since 3.1
 	 */
 	@SuppressWarnings("unchecked")
-	public static <K, V> MultiValueMap<K, V> unmodifiableMultiValueMap(MultiValueMap<? extends K, ? extends V> map) {
+	public static <K, V> MultiValueMap<K, V> unmodifiableMultiValueMap(
-		Assert.notNull(map, "'map' must not be null");
+			MultiValueMap<? extends K, ? extends V> targetMap) {
-		Map<K, List<V>> result = new LinkedHashMap<>(map.size());
+
-		map.forEach((key, value) -> {
+		Assert.notNull(targetMap, "'targetMap' must not be null");
+		Map<K, List<V>> result = new LinkedHashMap<>(targetMap.size());
+		targetMap.forEach((key, value) -> {
 			List<? extends V> values = Collections.unmodifiableList(value);
 			result.put(key, (List<V>) values);
 		});
@@ -467,141 +468,4 @@ public abstract class CollectionUtils {
 	}
 
 
-	/**
-	 * Adapts a Map to the MultiValueMap contract.
-	 */
-	@SuppressWarnings("serial")
-	private static class MultiValueMapAdapter<K, V> implements MultiValueMap<K, V>, Serializable {
-
-		private final Map<K, List<V>> map;
-
-		public MultiValueMapAdapter(Map<K, List<V>> map) {
-			Assert.notNull(map, "'map' must not be null");
-			this.map = map;
-		}
-
-		@Override
-		@Nullable
-		public V getFirst(K key) {
-			List<V> values = this.map.get(key);
-			return (values != null ? values.get(0) : null);
-		}
-
-		@Override
-		public void add(K key, @Nullable V value) {
-			List<V> values = this.map.computeIfAbsent(key, k -> new LinkedList<>());
-			values.add(value);
-		}
-
-		@Override
-		public void addAll(K key, List<? extends V> values) {
-			List<V> currentValues = this.map.computeIfAbsent(key, k -> new LinkedList<>());
-			currentValues.addAll(values);
-		}
-
-		@Override
-		public void addAll(MultiValueMap<K, V> values) {
-			for (Entry<K, List<V>> entry : values.entrySet()) {
-				addAll(entry.getKey(), entry.getValue());
-			}
-		}
-
-		@Override
-		public void set(K key, @Nullable V value) {
-			List<V> values = new LinkedList<>();
-			values.add(value);
-			this.map.put(key, values);
-		}
-
-		@Override
-		public void setAll(Map<K, V> values) {
-			values.forEach(this::set);
-		}
-
-		@Override
-		public Map<K, V> toSingleValueMap() {
-			LinkedHashMap<K, V> singleValueMap = new LinkedHashMap<>(this.map.size());
-			this.map.forEach((key, value) -> singleValueMap.put(key, value.get(0)));
-			return singleValueMap;
-		}
-
-		@Override
-		public int size() {
-			return this.map.size();
-		}
-
-		@Override
-		public boolean isEmpty() {
-			return this.map.isEmpty();
-		}
-
-		@Override
-		public boolean containsKey(Object key) {
-			return this.map.containsKey(key);
-		}
-
-		@Override
-		public boolean containsValue(Object value) {
-			return this.map.containsValue(value);
-		}
-
-		@Override
-		public List<V> get(Object key) {
-			return this.map.get(key);
-		}
-
-		@Override
-		public List<V> put(K key, List<V> value) {
-			return this.map.put(key, value);
-		}
-
-		@Override
-		public List<V> remove(Object key) {
-			return this.map.remove(key);
-		}
-
-		@Override
-		public void putAll(Map<? extends K, ? extends List<V>> map) {
-			this.map.putAll(map);
-		}
-
-		@Override
-		public void clear() {
-			this.map.clear();
-		}
-
-		@Override
-		public Set<K> keySet() {
-			return this.map.keySet();
-		}
-
-		@Override
-		public Collection<List<V>> values() {
-			return this.map.values();
-		}
-
-		@Override
-		public Set<Entry<K, List<V>>> entrySet() {
-			return this.map.entrySet();
-		}
-
-		@Override
-		public boolean equals(@Nullable Object other) {
-			if (this == other) {
-				return true;
-			}
-			return this.map.equals(other);
-		}
-
-		@Override
-		public int hashCode() {
-			return this.map.hashCode();
-		}
-
-		@Override
-		public String toString() {
-			return this.map.toString();
-		}
-	}
-
 }

spring-core/src/main/java/org/springframework/util/LinkedCaseInsensitiveMap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -273,8 +273,8 @@ public class LinkedCaseInsensitiveMap<V> implements Map<String, V>, Serializable
 	}
 
 	@Override
-	public boolean equals(@Nullable Object obj) {
+	public boolean equals(@Nullable Object other) {
-		return this.targetMap.equals(obj);
+		return (this == other || this.targetMap.equals(other));
 	}
 
 	@Override

spring-core/src/main/java/org/springframework/util/LinkedMultiValueMap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -17,14 +17,10 @@
 package org.springframework.util;
 
 import java.io.Serializable;
-import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
-
-import org.springframework.lang.Nullable;
 
 /**
  * Simple implementation of {@link MultiValueMap} that wraps a {@link LinkedHashMap},
@@ -39,18 +35,16 @@ import org.springframework.lang.Nullable;
  * @param <K> the key type
  * @param <V> the value element type
  */
-public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializable, Cloneable {
+public class LinkedMultiValueMap<K, V> extends MultiValueMapAdapter<K, V> implements Serializable, Cloneable {
 
 	private static final long serialVersionUID = 3801124242820219131L;
 
-	private final Map<K, List<V>> targetMap;
-
 
 	/**
 	 * Create a new LinkedMultiValueMap that wraps a {@link LinkedHashMap}.
 	 */
 	public LinkedMultiValueMap() {
-		this.targetMap = new LinkedHashMap<>();
+		super(new LinkedHashMap<>());
 	}
 
 	/**
@@ -59,7 +53,7 @@ public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializa
 	 * @param initialCapacity the initial capacity
 	 */
 	public LinkedMultiValueMap(int initialCapacity) {
-		this.targetMap = new LinkedHashMap<>(initialCapacity);
+		super(new LinkedHashMap<>(initialCapacity));
 	}
 
 	/**
@@ -71,125 +65,7 @@ public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializa
 	 * @see #deepCopy()
 	 */
 	public LinkedMultiValueMap(Map<K, List<V>> otherMap) {
-		this.targetMap = new LinkedHashMap<>(otherMap);
+		super(new LinkedHashMap<>(otherMap));
-	}
-
-
-	// MultiValueMap implementation
-
-	@Override
-	@Nullable
-	public V getFirst(K key) {
-		List<V> values = this.targetMap.get(key);
-		return (values != null && !values.isEmpty() ? values.get(0) : null);
-	}
-
-	@Override
-	public void add(K key, @Nullable V value) {
-		List<V> values = this.targetMap.computeIfAbsent(key, k -> new LinkedList<>());
-		values.add(value);
-	}
-
-	@Override
-	public void addAll(K key, List<? extends V> values) {
-		List<V> currentValues = this.targetMap.computeIfAbsent(key, k -> new LinkedList<>());
-		currentValues.addAll(values);
-	}
-
-	@Override
-	public void addAll(MultiValueMap<K, V> values) {
-		for (Entry<K, List<V>> entry : values.entrySet()) {
-			addAll(entry.getKey(), entry.getValue());
-		}
-	}
-
-	@Override
-	public void set(K key, @Nullable V value) {
-		List<V> values = new LinkedList<>();
-		values.add(value);
-		this.targetMap.put(key, values);
-	}
-
-	@Override
-	public void setAll(Map<K, V> values) {
-		values.forEach(this::set);
-	}
-
-	@Override
-	public Map<K, V> toSingleValueMap() {
-		LinkedHashMap<K, V> singleValueMap = new LinkedHashMap<>(this.targetMap.size());
-		this.targetMap.forEach((key, values) -> {
-			if (values != null && !values.isEmpty()) {
-				singleValueMap.put(key, values.get(0));
-			}
-		});
-		return singleValueMap;
-	}
-
-
-	// Map implementation
-
-	@Override
-	public int size() {
-		return this.targetMap.size();
-	}
-
-	@Override
-	public boolean isEmpty() {
-		return this.targetMap.isEmpty();
-	}
-
-	@Override
-	public boolean containsKey(Object key) {
-		return this.targetMap.containsKey(key);
-	}
-
-	@Override
-	public boolean containsValue(Object value) {
-		return this.targetMap.containsValue(value);
-	}
-
-	@Override
-	@Nullable
-	public List<V> get(Object key) {
-		return this.targetMap.get(key);
-	}
-
-	@Override
-	@Nullable
-	public List<V> put(K key, List<V> value) {
-		return this.targetMap.put(key, value);
-	}
-
-	@Override
-	@Nullable
-	public List<V> remove(Object key) {
-		return this.targetMap.remove(key);
-	}
-
-	@Override
-	public void putAll(Map<? extends K, ? extends List<V>> map) {
-		this.targetMap.putAll(map);
-	}
-
-	@Override
-	public void clear() {
-		this.targetMap.clear();
-	}
-
-	@Override
-	public Set<K> keySet() {
-		return this.targetMap.keySet();
-	}
-
-	@Override
-	public Collection<List<V>> values() {
-		return this.targetMap.values();
-	}
-
-	@Override
-	public Set<Entry<K, List<V>>> entrySet() {
-		return this.targetMap.entrySet();
 	}
 
 
@@ -203,8 +79,8 @@ public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializa
 	 * @see #clone()
 	 */
 	public LinkedMultiValueMap<K, V> deepCopy() {
-		LinkedMultiValueMap<K, V> copy = new LinkedMultiValueMap<>(this.targetMap.size());
+		LinkedMultiValueMap<K, V> copy = new LinkedMultiValueMap<>(size());
-		this.targetMap.forEach((key, value) -> copy.put(key, new LinkedList<>(value)));
+		forEach((key, values) -> copy.put(key, new LinkedList<>(values)));
 		return copy;
 	}
 
@@ -224,19 +100,4 @@ public class LinkedMultiValueMap<K, V> implements MultiValueMap<K, V>, Serializa
 		return new LinkedMultiValueMap<>(this);
 	}
 
-	@Override
-	public boolean equals(@Nullable Object obj) {
-		return this.targetMap.equals(obj);
-	}
-
-	@Override
-	public int hashCode() {
-		return this.targetMap.hashCode();
-	}
-
-	@Override
-	public String toString() {
-		return this.targetMap.toString();
-	}
-
 }

spring-core/src/main/java/org/springframework/util/MultiValueMapAdapter.java

@@ -0,0 +1,178 @@
+/*
+ * Copyright 2002-2020 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
+ *
+ *      https://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.util;
+
+import java.io.Serializable;
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * Adapts a given {@link Map} to the {@link MultiValueMap} contract.
+ *
+ * @author Arjen Poutsma
+ * @author Juergen Hoeller
+ * @since 3.1
+ * @param <K> the key type
+ * @param <V> the value element type
+ * @see CollectionUtils#toMultiValueMap
+ * @see LinkedMultiValueMap
+ */
+@SuppressWarnings("serial")
+class MultiValueMapAdapter<K, V> implements MultiValueMap<K, V>, Serializable {
+
+	private final Map<K, List<V>> targetMap;
+
+
+	MultiValueMapAdapter(Map<K, List<V>> targetMap) {
+		this.targetMap = targetMap;
+	}
+
+
+	@Override
+	@Nullable
+	public V getFirst(K key) {
+		List<V> values = this.targetMap.get(key);
+		return (values != null && !values.isEmpty() ? values.get(0) : null);
+	}
+
+	@Override
+	public void add(K key, @Nullable V value) {
+		List<V> values = this.targetMap.computeIfAbsent(key, k -> new LinkedList<>());
+		values.add(value);
+	}
+
+	@Override
+	public void addAll(K key, List<? extends V> values) {
+		List<V> currentValues = this.targetMap.computeIfAbsent(key, k -> new LinkedList<>());
+		currentValues.addAll(values);
+	}
+
+	@Override
+	public void addAll(MultiValueMap<K, V> values) {
+		for (Entry<K, List<V>> entry : values.entrySet()) {
+			addAll(entry.getKey(), entry.getValue());
+		}
+	}
+
+	@Override
+	public void set(K key, @Nullable V value) {
+		List<V> values = new LinkedList<>();
+		values.add(value);
+		this.targetMap.put(key, values);
+	}
+
+	@Override
+	public void setAll(Map<K, V> values) {
+		values.forEach(this::set);
+	}
+
+	@Override
+	public Map<K, V> toSingleValueMap() {
+		Map<K, V> singleValueMap = new LinkedHashMap<>(this.targetMap.size());
+		this.targetMap.forEach((key, values) -> {
+			if (values != null && !values.isEmpty()) {
+				singleValueMap.put(key, values.get(0));
+			}
+		});
+		return singleValueMap;
+	}
+
+	@Override
+	public int size() {
+		return this.targetMap.size();
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return this.targetMap.isEmpty();
+	}
+
+	@Override
+	public boolean containsKey(Object key) {
+		return this.targetMap.containsKey(key);
+	}
+
+	@Override
+	public boolean containsValue(Object value) {
+		return this.targetMap.containsValue(value);
+	}
+
+	@Override
+	@Nullable
+	public List<V> get(Object key) {
+		return this.targetMap.get(key);
+	}
+
+	@Override
+	@Nullable
+	public List<V> put(K key, List<V> value) {
+		return this.targetMap.put(key, value);
+	}
+
+	@Override
+	@Nullable
+	public List<V> remove(Object key) {
+		return this.targetMap.remove(key);
+	}
+
+	@Override
+	public void putAll(Map<? extends K, ? extends List<V>> map) {
+		this.targetMap.putAll(map);
+	}
+
+	@Override
+	public void clear() {
+		this.targetMap.clear();
+	}
+
+	@Override
+	public Set<K> keySet() {
+		return this.targetMap.keySet();
+	}
+
+	@Override
+	public Collection<List<V>> values() {
+		return this.targetMap.values();
+	}
+
+	@Override
+	public Set<Entry<K, List<V>>> entrySet() {
+		return this.targetMap.entrySet();
+	}
+
+	@Override
+	public boolean equals(@Nullable Object other) {
+		return (this == other || this.targetMap.equals(other));
+	}
+
+	@Override
+	public int hashCode() {
+		return this.targetMap.hashCode();
+	}
+
+	@Override
+	public String toString() {
+		return this.targetMap.toString();
+	}
+
+}

spring-core/src/main/java/org/springframework/util/SystemPropertyUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -78,6 +78,9 @@ public abstract class SystemPropertyUtils {
 	 * and the "ignoreUnresolvablePlaceholders" flag is {@code false}
 	 */
 	public static String resolvePlaceholders(String text, boolean ignoreUnresolvablePlaceholders) {
+		if (text.isEmpty()) {
+			return text;
+		}
 		PropertyPlaceholderHelper helper = (ignoreUnresolvablePlaceholders ? nonStrictHelper : strictHelper);
 		return helper.replacePlaceholders(text, new SystemPropertyPlaceholderResolver(text));
 	}

spring-jdbc/src/main/java/org/springframework/jdbc/core/JdbcOperations.java

@@ -965,6 +965,8 @@ public interface JdbcOperations {
 	 * @param pss object to set parameters on the PreparedStatement
 	 * created by this method
 	 * @return an array of the number of rows affected by each statement
+	 * (may also contain special JDBC-defined negative values for affected rows such as
+	 * {@link java.sql.Statement#SUCCESS_NO_INFO}/{@link java.sql.Statement#EXECUTE_FAILED})
 	 * @throws DataAccessException if there is any problem issuing the update
 	 */
 	int[] batchUpdate(String sql, BatchPreparedStatementSetter pss) throws DataAccessException;
@@ -974,6 +976,8 @@ public interface JdbcOperations {
 	 * @param sql the SQL statement to execute
 	 * @param batchArgs the List of Object arrays containing the batch of arguments for the query
 	 * @return an array containing the numbers of rows affected by each update in the batch
+	 * (may also contain special JDBC-defined negative values for affected rows such as
+	 * {@link java.sql.Statement#SUCCESS_NO_INFO}/{@link java.sql.Statement#EXECUTE_FAILED})
 	 * @throws DataAccessException if there is any problem issuing the update
 	 */
 	int[] batchUpdate(String sql, List<Object[]> batchArgs) throws DataAccessException;
@@ -985,20 +989,24 @@ public interface JdbcOperations {
 	 * @param argTypes the SQL types of the arguments
 	 * (constants from {@code java.sql.Types})
 	 * @return an array containing the numbers of rows affected by each update in the batch
+	 * (may also contain special JDBC-defined negative values for affected rows such as
+	 * {@link java.sql.Statement#SUCCESS_NO_INFO}/{@link java.sql.Statement#EXECUTE_FAILED})
 	 * @throws DataAccessException if there is any problem issuing the update
 	 */
 	int[] batchUpdate(String sql, List<Object[]> batchArgs, int[] argTypes) throws DataAccessException;
 
 	/**
-	 * Execute multiple batches using the supplied SQL statement with the collect of supplied arguments.
+	 * Execute multiple batches using the supplied SQL statement with the collect of supplied
-	 * The arguments' values will be set using the ParameterizedPreparedStatementSetter.
+	 * arguments. The arguments' values will be set using the ParameterizedPreparedStatementSetter.
 	 * Each batch should be of size indicated in 'batchSize'.
 	 * @param sql the SQL statement to execute.
 	 * @param batchArgs the List of Object arrays containing the batch of arguments for the query
 	 * @param batchSize batch size
 	 * @param pss the ParameterizedPreparedStatementSetter to use
-	 * @return an array containing for each batch another array containing the numbers of rows affected
+	 * @return an array containing for each batch another array containing the numbers of
-	 * by each update in the batch
+	 * rows affected by each update in the batch
+	 * (may also contain special JDBC-defined negative values for affected rows such as
+	 * {@link java.sql.Statement#SUCCESS_NO_INFO}/{@link java.sql.Statement#EXECUTE_FAILED})
 	 * @throws DataAccessException if there is any problem issuing the update
 	 * @since 3.1
 	 */

spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/NamedParameterJdbcOperations.java

@@ -530,6 +530,8 @@ public interface NamedParameterJdbcOperations {
 	 * @param sql the SQL statement to execute
 	 * @param batchValues the array of Maps containing the batch of arguments for the query
 	 * @return an array containing the numbers of rows affected by each update in the batch
+	 * (may also contain special JDBC-defined negative values for affected rows such as
+	 * {@link java.sql.Statement#SUCCESS_NO_INFO}/{@link java.sql.Statement#EXECUTE_FAILED})
 	 * @throws DataAccessException if there is any problem issuing the update
 	 */
 	int[] batchUpdate(String sql, Map<String, ?>[] batchValues);
@@ -537,8 +539,11 @@ public interface NamedParameterJdbcOperations {
 	/**
 	 * Execute a batch using the supplied SQL statement with the batch of supplied arguments.
 	 * @param sql the SQL statement to execute
-	 * @param batchArgs the array of {@link SqlParameterSource} containing the batch of arguments for the query
+	 * @param batchArgs the array of {@link SqlParameterSource} containing the batch of
+	 * arguments for the query
 	 * @return an array containing the numbers of rows affected by each update in the batch
+	 * (may also contain special JDBC-defined negative values for affected rows such as
+	 * {@link java.sql.Statement#SUCCESS_NO_INFO}/{@link java.sql.Statement#EXECUTE_FAILED})
 	 * @throws DataAccessException if there is any problem issuing the update
 	 */
 	int[] batchUpdate(String sql, SqlParameterSource[] batchArgs);

spring-orm/src/main/java/org/springframework/orm/hibernate5/support/OpenSessionInViewFilter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -51,11 +51,11 @@ import org.springframework.web.filter.OncePerRequestFilter;
  * as well as for non-transactional execution (if configured appropriately).
  *
  * <p><b>NOTE</b>: This filter will by default <i>not</i> flush the Hibernate Session,
- * with the flush mode set to {@code FlushMode.NEVER}. It assumes to be used
+ * with the flush mode set to {@code FlushMode.MANUAL}. It assumes to be used
  * in combination with service layer transactions that care for the flushing: The
  * active transaction manager will temporarily change the flush mode to
  * {@code FlushMode.AUTO} during a read-write transaction, with the flush
- * mode reset to {@code FlushMode.NEVER} at the end of each transaction.
+ * mode reset to {@code FlushMode.MANUAL} at the end of each transaction.
  *
  * <p><b>WARNING:</b> Applying this filter to existing logic can cause issues that
  * have not appeared before, through the use of a single Hibernate Session for the

spring-tx/src/main/java/org/springframework/transaction/support/TransactionSynchronizationManager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -383,7 +383,7 @@ public abstract class TransactionSynchronizationManager {
 	 * as argument for the {@code beforeCommit} callback, to be able
 	 * to suppress change detection on commit. The present method is meant
 	 * to be used for earlier read-only checks, for example to set the
-	 * flush mode of a Hibernate Session to "FlushMode.NEVER" upfront.
+	 * flush mode of a Hibernate Session to "FlushMode.MANUAL" upfront.
 	 * @see org.springframework.transaction.TransactionDefinition#isReadOnly()
 	 * @see TransactionSynchronization#beforeCommit(boolean)
 	 */

spring-web/src/main/java/org/springframework/web/util/ServletContextPropertyUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.web.util;
 
 import javax.servlet.ServletContext;
@@ -73,16 +74,18 @@ public abstract class ServletContextPropertyUtils {
 	 * @see SystemPropertyUtils#PLACEHOLDER_SUFFIX
 	 * @see SystemPropertyUtils#resolvePlaceholders(String, boolean)
 	 */
-	public static String resolvePlaceholders(String text, ServletContext servletContext,
+	public static String resolvePlaceholders(
-			boolean ignoreUnresolvablePlaceholders) {
+			String text, ServletContext servletContext, boolean ignoreUnresolvablePlaceholders) {
 
+		if (text.isEmpty()) {
+			return text;
+		}
 		PropertyPlaceholderHelper helper = (ignoreUnresolvablePlaceholders ? nonStrictHelper : strictHelper);
 		return helper.replacePlaceholders(text, new ServletContextPlaceholderResolver(text, servletContext));
 	}
 
 
-	private static class ServletContextPlaceholderResolver
+	private static class ServletContextPlaceholderResolver implements PropertyPlaceholderHelper.PlaceholderResolver {
-			implements PropertyPlaceholderHelper.PlaceholderResolver {
 
 		private final String text;