Optimize Entry hashCode in HttpHeaders (plus related polishing)

spring-web/src/main/java/org/springframework/http/HttpHeaders.java

@@ -2188,6 +2188,7 @@ public class HttpHeaders implements Serializable {
 		private static final Object VALUE = new Object();
 
 		private final MultiValueMap<String, String> headers;
+
 		private final Map<String, Object> deduplicatedNames;
 
 		public CaseInsensitiveHeaderNameSet(MultiValueMap<String, String> headers) {
@@ -2229,13 +2230,15 @@ public class HttpHeaders implements Serializable {
 		}
 	}
 
-	private static class HeaderNamesIterator implements Iterator<String> {
 
-		private @Nullable String currentName;
+	private static class HeaderNamesIterator implements Iterator<String> {
 
 		private final MultiValueMap<String, String> headers;
+
 		private final Iterator<String> namesIterator;
 
+		private @Nullable String currentName;
+
 		public HeaderNamesIterator(MultiValueMap<String, String> headers, Map<String, Object> caseInsensitiveNames) {
 			this.headers = headers;
 			this.namesIterator = caseInsensitiveNames.keySet().iterator();
@@ -2269,6 +2272,7 @@ public class HttpHeaders implements Serializable {
 	private static final class CaseInsensitiveEntrySet extends AbstractSet<Entry<String, List<String>>> {
 
 		private final MultiValueMap<String, String> headers;
+
 		private final CaseInsensitiveHeaderNameSet nameSet;
 
 		public CaseInsensitiveEntrySet(MultiValueMap<String, String> headers) {
@@ -2286,6 +2290,7 @@ public class HttpHeaders implements Serializable {
 			return this.nameSet.size();
 		}
 
+
 		private final class CaseInsensitiveIterator implements Iterator<Entry<String, List<String>>> {
 
 			private final Iterator<String> namesIterator;
@@ -2310,6 +2315,7 @@ public class HttpHeaders implements Serializable {
 			}
 		}
 
+
 		private final class CaseInsensitiveEntry implements Entry<String, List<String>> {
 
 			private final String key;
@@ -2330,26 +2336,21 @@ public class HttpHeaders implements Serializable {
 
 			@Override
 			public List<String> setValue(List<String> value) {
-				List<String> previousValues = Objects.requireNonNull(
-						CaseInsensitiveEntrySet.this.headers.get(this.key));
+				List<String> previousValues = Objects.requireNonNull(CaseInsensitiveEntrySet.this.headers.get(this.key));
 				CaseInsensitiveEntrySet.this.headers.put(this.key, value);
 				return previousValues;
 			}
 
 			@Override
-			public boolean equals(@Nullable Object o) {
-				if (this == o) {
-					return true;
-				}
-				if (!(o instanceof Map.Entry<?,?> that)) {
-					return false;
-				}
-				return ObjectUtils.nullSafeEquals(getKey(), that.getKey()) && ObjectUtils.nullSafeEquals(getValue(), that.getValue());
+			public boolean equals(@Nullable Object other) {
+				return (this == other || (other instanceof Map.Entry<?, ?> that &&
+						ObjectUtils.nullSafeEquals(getKey(), that.getKey()) &&
+						ObjectUtils.nullSafeEquals(getValue(), that.getValue())));
 			}
 
 			@Override
 			public int hashCode() {
-				return ObjectUtils.nullSafeHash(getKey(), getValue());
+				return this.key.hashCode();  // avoid value lookup for hashCode
 			}
 		}
 	}

spring-web/src/main/java/org/springframework/http/support/JettyHeadersAdapter.java

@@ -52,14 +52,14 @@ public final class JettyHeadersAdapter implements MultiValueMap<String, String>
 
 
 	/**
-	 * Creates a new {@code JettyHeadersAdapter} based on the given
+	 * Construct a new {@code JettyHeadersAdapter} based on the given
 	 * {@code HttpFields} instance.
 	 * @param headers the {@code HttpFields} to base this adapter on
 	 */
 	public JettyHeadersAdapter(HttpFields headers) {
 		Assert.notNull(headers, "Headers must not be null");
 		this.headers = headers;
-		this.mutable = headers instanceof HttpFields.Mutable m ? m : null;
+		this.mutable = (headers instanceof HttpFields.Mutable m ? m : null);
 	}
 
 
@@ -146,12 +146,12 @@ public final class JettyHeadersAdapter implements MultiValueMap<String, String>
 	public @Nullable List<String> get(Object key) {
 		List<String> list = null;
 		if (key instanceof String name) {
-			for (HttpField f : this.headers) {
-				if (f.is(name)) {
+			for (HttpField field : this.headers) {
+				if (field.is(name)) {
 					if (list == null) {
 						list = new ArrayList<>();
 					}
-					list.add(f.getValue());
+					list.add(field.getValue());
 				}
 			}
 		}
@@ -162,7 +162,6 @@ public final class JettyHeadersAdapter implements MultiValueMap<String, String>
 	public @Nullable List<String> put(String key, List<String> value) {
 		HttpFields.Mutable mutableHttpFields = mutableFields();
 		List<String> oldValues = get(key);
-
 		if (oldValues == null) {
 			switch (value.size()) {
 				case 0 -> {}