Use Map.forEach instead of manual Map.Entry iteration wherever possible

spring-context/src/main/java/org/springframework/remoting/support/SimpleHttpServerFactoryBean.java

@@ -153,15 +153,15 @@ public void afterPropertiesSet() throws IOException {
 			this.server.setExecutor(this.executor);
 		}
 		if (this.contexts != null) {
-			for (String key : this.contexts.keySet()) {
-				HttpContext httpContext = this.server.createContext(key, this.contexts.get(key));
+			this.contexts.forEach((key, context) -> {
+				HttpContext httpContext = this.server.createContext(key, context);
 				if (this.filters != null) {
 					httpContext.getFilters().addAll(this.filters);
 				}
 				if (this.authenticator != null) {
 					httpContext.setAuthenticator(this.authenticator);
 				}
-			}
+			});
 		}
 		if (this.logger.isInfoEnabled()) {
 			this.logger.info("Starting HttpServer at address " + address);

spring-messaging/src/main/java/org/springframework/messaging/simp/broker/DefaultSubscriptionRegistry.java

@@ -196,8 +196,8 @@ private MultiValueMap<String, String> filterSubscriptions(
 			return allMatches;
 		}
 		MultiValueMap<String, String> result = new LinkedMultiValueMap<>(allMatches.size());
-		for (String sessionId : allMatches.keySet()) {
-			for (String subId : allMatches.get(sessionId)) {
+		allMatches.forEach((sessionId, subIds) -> {
+			for (String subId : subIds) {
 				SessionSubscriptionInfo info = this.subscriptionRegistry.getSubscriptions(sessionId);
 				if (info == null) {
 					continue;
@@ -225,7 +225,7 @@ private MultiValueMap<String, String> filterSubscriptions(
 					logger.debug("Failed to evaluate selector", ex);
 				}
 			}
-		}
+		});
 		return result;
 	}
 

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletRequest.java

@@ -526,8 +526,7 @@ public void setParameter(String name, String... values) {
 	 */
 	public void setParameters(Map<String, ?> params) {
 		Assert.notNull(params, "Parameter map must not be null");
-		for (String key : params.keySet()) {
-			Object value = params.get(key);
+		params.forEach((key, value) -> {
 			if (value instanceof String) {
 				setParameter(key, (String) value);
 			}
@@ -538,7 +537,7 @@ else if (value instanceof String[]) {
 				throw new IllegalArgumentException(
 						"Parameter map value must be single value " + " or array of type [" + String.class.getName() + "]");
 			}
-		}
+		});
 	}
 
 	/**
@@ -576,8 +575,7 @@ public void addParameter(String name, String... values) {
 	 */
 	public void addParameters(Map<String, ?> params) {
 		Assert.notNull(params, "Parameter map must not be null");
-		for (String key : params.keySet()) {
-			Object value = params.get(key);
+		params.forEach((key, value) -> {
 			if (value instanceof String) {
 				addParameter(key, (String) value);
 			}
@@ -588,7 +586,7 @@ else if (value instanceof String[]) {
 				throw new IllegalArgumentException("Parameter map value must be single value " +
 						" or array of type [" + String.class.getName() + "]");
 			}
-		}
+		});
 	}
 
 	/**

spring-test/src/main/java/org/springframework/test/web/ModelAndViewAssert.java

@@ -118,14 +118,13 @@ public static void assertModelAttributeValues(ModelAndView mav, Map<String, Obje
 		}
 
 		StringBuilder sb = new StringBuilder();
-		for (String modelName : model.keySet()) {
+		model.forEach((modelName, mavValue) -> {
 			Object assertionValue = expectedModel.get(modelName);
-			Object mavValue = model.get(modelName);
 			if (!assertionValue.equals(mavValue)) {
 				sb.append("Value under name '").append(modelName).append("' differs, should have been '").append(
 					assertionValue).append("' but was '").append(mavValue).append("'\n");
 			}
-		}
+		});
 
 		if (sb.length() != 0) {
 			sb.insert(0, "Values of expected model do not match.\n");

spring-test/src/main/java/org/springframework/test/web/servlet/request/MockHttpServletRequestBuilder.java

@@ -345,11 +345,11 @@ public MockHttpServletRequestBuilder param(String name, String... values) {
 	 * @since 4.2.4
 	 */
 	public MockHttpServletRequestBuilder params(MultiValueMap<String, String> params) {
-		for (String name : params.keySet()) {
-			for (String value : params.get(name)) {
+		params.forEach((name, values) -> {
+			for (String value : values) {
 				this.parameters.add(name, value);
 			}
-		}
+		});
 		return this;
 	}
 
@@ -414,9 +414,7 @@ public MockHttpServletRequestBuilder sessionAttr(String name, Object value) {
 	 */
 	public MockHttpServletRequestBuilder sessionAttrs(Map<String, Object> sessionAttributes) {
 		Assert.notEmpty(sessionAttributes, "'sessionAttributes' must not be empty");
-		for (String name : sessionAttributes.keySet()) {
-			sessionAttr(name, sessionAttributes.get(name));
-		}
+		sessionAttributes.forEach(this::sessionAttr);
 		return this;
 	}
 
@@ -436,9 +434,7 @@ public MockHttpServletRequestBuilder flashAttr(String name, Object value) {
 	 */
 	public MockHttpServletRequestBuilder flashAttrs(Map<String, Object> flashAttributes) {
 		Assert.notEmpty(flashAttributes, "'flashAttributes' must not be empty");
-		for (String name : flashAttributes.keySet()) {
-			flashAttr(name, flashAttributes.get(name));
-		}
+		flashAttributes.forEach(this::flashAttr);
 		return this;
 	}
 
@@ -624,22 +620,22 @@ public final MockHttpServletRequest buildRequest(ServletContext servletContext)
 		request.setContent(this.content);
 		request.setContentType(this.contentType);
 
-		for (String name : this.headers.keySet()) {
-			for (Object value : this.headers.get(name)) {
+		this.headers.forEach((name, values) -> {
+			for (Object value : values) {
 				request.addHeader(name, value);
 			}
-		}
+		});
 
 		if (this.url.getRawQuery() != null) {
 			request.setQueryString(this.url.getRawQuery());
 		}
 		addRequestParams(request, UriComponentsBuilder.fromUri(this.url).build().getQueryParams());
 
-		for (String name : this.parameters.keySet()) {
-			for (String value : this.parameters.get(name)) {
+		this.parameters.forEach((name, values) -> {
+			for (String value : values) {
 				request.addParameter(name, value);
 			}
-		}
+		});
 
 		if (this.content != null && this.content.length > 0) {
 			String requestContentType = request.getContentType();
@@ -658,14 +654,12 @@ public final MockHttpServletRequest buildRequest(ServletContext servletContext)
 			request.setPreferredLocales(this.locales);
 		}
 
-		for (String name : this.requestAttributes.keySet()) {
-			request.setAttribute(name, this.requestAttributes.get(name));
-		}
-		for (String name : this.sessionAttributes.keySet()) {
+		this.requestAttributes.forEach(request::setAttribute);
+		this.sessionAttributes.forEach((name, attribute) -> {
 			HttpSession session = request.getSession();
 			Assert.state(session != null, "No HttpSession");
-			session.setAttribute(name, this.sessionAttributes.get(name));
-		}
+			session.setAttribute(name, attribute);
+		});
 
 		FlashMap flashMap = new FlashMap();
 		flashMap.putAll(this.flashAttributes);

spring-test/src/main/java/org/springframework/test/web/servlet/result/PrintingResultHandler.java

@@ -135,13 +135,13 @@ protected final HttpHeaders getRequestHeaders(MockHttpServletRequest request) {
 	protected final MultiValueMap<String, String> getParamsMultiValueMap(MockHttpServletRequest request) {
 		Map<String, String[]> params = request.getParameterMap();
 		MultiValueMap<String, String> multiValueMap = new LinkedMultiValueMap<>();
-		for (String name : params.keySet()) {
+		params.forEach((name, values) -> {
 			if (params.get(name) != null) {
-				for (String value : params.get(name)) {
+				for (String value : values) {
 					multiValueMap.add(name, value);
 				}
 			}
-		}
+		});
 		return multiValueMap;
 	}
 
@@ -235,10 +235,10 @@ protected void printFlashMap(FlashMap flashMap) throws Exception {
 			this.printer.printValue("Attributes", null);
 		}
 		else {
-			for (String name : flashMap.keySet()) {
+			flashMap.forEach((name, value) -> {
 				this.printer.printValue("Attribute", name);
-				this.printer.printValue("value", flashMap.get(name));
-			}
+				this.printer.printValue("value", value);
+			});
 		}
 	}
 

spring-web/src/main/java/org/springframework/http/converter/json/Jackson2ObjectMapperBuilder.java

@@ -660,9 +660,7 @@ else if (this.findWellKnownModules) {
 			objectMapper.setFilterProvider(this.filters);
 		}
 
-		for (Class<?> target : this.mixIns.keySet()) {
-			objectMapper.addMixIn(target, this.mixIns.get(target));
-		}
+		this.mixIns.forEach((target, mixinSource) -> objectMapper.addMixIn(target, mixinSource));
 
 		if (!this.serializers.isEmpty() || !this.deserializers.isEmpty()) {
 			SimpleModule module = new SimpleModule();
@@ -672,9 +670,7 @@ else if (this.findWellKnownModules) {
 		}
 
 		customizeDefaultFeatures(objectMapper);
-		for (Object feature : this.features.keySet()) {
-			configureFeature(objectMapper, feature, this.features.get(feature));
-		}
+		this.features.forEach((feature, enabled) -> configureFeature(objectMapper, feature, enabled));
 
 		if (this.handlerInstantiator != null) {
 			objectMapper.setHandlerInstantiator(this.handlerInstantiator);
@@ -699,16 +695,14 @@ private void customizeDefaultFeatures(ObjectMapper objectMapper) {
 
 	@SuppressWarnings("unchecked")
 	private <T> void addSerializers(SimpleModule module) {
-		for (Class<?> type : this.serializers.keySet()) {
-			module.addSerializer((Class<? extends T>) type, (JsonSerializer<T>) this.serializers.get(type));
-		}
+		this.serializers.forEach((type, serializer) ->
+				module.addSerializer((Class<? extends T>) type, (JsonSerializer<T>) serializer));
 	}
 
 	@SuppressWarnings("unchecked")
 	private <T> void addDeserializers(SimpleModule module) {
-		for (Class<?> type : this.deserializers.keySet()) {
-			module.addDeserializer((Class<T>) type, (JsonDeserializer<? extends T>) this.deserializers.get(type));
-		}
+		this.deserializers.forEach((type, deserializer) ->
+				module.addDeserializer((Class<T>) type, (JsonDeserializer<? extends T>) deserializer));
 	}
 
 	private void configureFeature(ObjectMapper objectMapper, Object feature, boolean enabled) {

spring-web/src/main/java/org/springframework/web/method/annotation/SessionAttributesHandler.java

@@ -112,12 +112,11 @@ public boolean isHandlerSessionAttribute(String attributeName, Class<?> attribut
 	 * @param attributes candidate attributes for session storage
 	 */
 	public void storeAttributes(WebRequest request, Map<String, ?> attributes) {
-		for (String name : attributes.keySet()) {
-			Object value = attributes.get(name);
+		attributes.forEach((name, value) -> {
 			if (value != null && isHandlerSessionAttribute(name, value.getClass())) {
 				this.sessionAttributeStore.storeAttribute(request, name, value);
 			}
-		}
+		});
 	}
 
 	/**

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

@@ -567,11 +567,11 @@ public MultiValueMap<String, String> decodeMatrixVariables(HttpServletRequest re
 		}
 		else {
 			MultiValueMap<String, String> decodedVars = new LinkedMultiValueMap<>(vars.size());
-			for (String key : vars.keySet()) {
-				for (String value : vars.get(key)) {
+			vars.forEach((key, values) -> {
+				for (String value : values) {
 					decodedVars.add(key, decodeInternal(request, value));
 				}
-			}
+			});
 			return decodedVars;
 		}
 	}

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/MatrixVariableMapMethodArgumentResolver.java

@@ -90,11 +90,11 @@ public Object resolveArgumentValue(MethodParameter parameter, BindingContext bin
 		}
 		else {
 			for (MultiValueMap<String, String> vars : matrixVariables.values()) {
-				for (String name : vars.keySet()) {
-					for (String value : vars.get(name)) {
+				vars.forEach((name, values) -> {
+					for (String value : values) {
 						map.add(name, value);
 					}
-				}
+				});
 			}
 		}
 

spring-webmvc/src/main/java/org/springframework/web/servlet/FlashMap.java

@@ -80,11 +80,11 @@ public String getTargetRequestPath() {
 	 */
 	public FlashMap addTargetRequestParams(@Nullable MultiValueMap<String, String> params) {
 		if (params != null) {
-			for (String key : params.keySet()) {
-				for (String value : params.get(key)) {
+			params.forEach((key, values) -> {
+				for (String value : values) {
 					addTargetRequestParam(key, value);
 				}
-			}
+			});
 		}
 		return this;
 	}

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

@@ -86,11 +86,11 @@ public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewC
 		}
 		else {
 			for (MultiValueMap<String, String> vars : matrixVariables.values()) {
-				for (String name : vars.keySet()) {
-					for (String value : vars.get(name)) {
+				vars.forEach((name, values) -> {
+					for (String value : values) {
 						map.add(name, value);
 					}
-				}
+				});
 			}
 		}
 

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/support/RedirectAttributesModelMap.java

@@ -111,9 +111,7 @@ public RedirectAttributesModelMap addAllAttributes(@Nullable Collection<?> attri
 	@Override
 	public RedirectAttributesModelMap addAllAttributes(@Nullable Map<String, ?> attributes) {
 		if (attributes != null) {
-			for (String key : attributes.keySet()) {
-				addAttribute(key, attributes.get(key));
-			}
+			attributes.forEach(this::addAttribute);
 		}
 		return this;
 	}
@@ -125,11 +123,11 @@ public RedirectAttributesModelMap addAllAttributes(@Nullable Map<String, ?> attr
 	@Override
 	public RedirectAttributesModelMap mergeAttributes(@Nullable Map<String, ?> attributes) {
 		if (attributes != null) {
-			for (String key : attributes.keySet()) {
+			attributes.forEach((key, attribute) -> {
 				if (!containsKey(key)) {
-					addAttribute(key, attributes.get(key));
+					addAttribute(key, attribute);
 				}
-			}
+			});
 		}
 		return this;
 	}
@@ -155,9 +153,7 @@ public Object put(String key, @Nullable Object value) {
 	@Override
 	public void putAll(@Nullable Map<? extends String, ? extends Object> map) {
 		if (map != null) {
-			for (String key : map.keySet()) {
-				put(key, formatValue(map.get(key)));
-			}
+			map.forEach((key, value) -> put(key, formatValue(value)));
 		}
 	}
 

spring-websocket/src/main/java/org/springframework/web/socket/client/AbstractWebSocketClient.java

@@ -84,12 +84,11 @@ public final ListenableFuture<WebSocketSession> doHandshake(WebSocketHandler web
 
 		HttpHeaders headersToUse = new HttpHeaders();
 		if (headers != null) {
-			for (String header : headers.keySet()) {
-				List<String> values = headers.get(header);
+			headers.forEach((header, values) -> {
 				if (values != null && !specialHeaders.contains(header.toLowerCase())) {
 					headersToUse.put(header, values);
 				}
-			}
+			});
 		}
 
 		List<String> subProtocols =

spring-websocket/src/main/java/org/springframework/web/socket/client/jetty/JettyWebSocketClient.java

@@ -147,9 +147,7 @@ public ListenableFuture<WebSocketSession> doHandshakeInternal(WebSocketHandler w
 			request.addExtensions(new WebSocketToJettyExtensionConfigAdapter(e));
 		}
 
-		for (String header : headers.keySet()) {
-			request.setHeader(header, headers.get(header));
-		}
+		headers.forEach(request::setHeader);
 
 		Principal user = getUser();
 		final JettyWebSocketSession wsSession = new JettyWebSocketSession(attributes, user);