Polish: Lambdas should be replaced with method references

spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java

@@ -744,8 +744,8 @@ public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFacto
 						final FactoryBean<?> factory = (FactoryBean<?>) bean;
 						boolean isEagerInit;
 						if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
-							isEagerInit = AccessController.doPrivileged((PrivilegedAction<Boolean>) () ->
-											((SmartFactoryBean<?>) factory).isEagerInit(),
+							isEagerInit = AccessController.doPrivileged((PrivilegedAction<Boolean>)
+											((SmartFactoryBean<?>) factory)::isEagerInit,
 									getAccessControlContext());
 						}
 						else {

spring-beans/src/main/java/org/springframework/beans/factory/support/FactoryBeanRegistrySupport.java

@@ -57,8 +57,8 @@ public abstract class FactoryBeanRegistrySupport extends DefaultSingletonBeanReg
 	protected Class<?> getTypeForFactoryBean(final FactoryBean<?> factoryBean) {
 		try {
 			if (System.getSecurityManager() != null) {
-				return AccessController.doPrivileged((PrivilegedAction<Class<?>>) () ->
-						factoryBean.getObjectType(), getAccessControlContext());
+				return AccessController.doPrivileged((PrivilegedAction<Class<?>>)
+						factoryBean::getObjectType, getAccessControlContext());
 			}
 			else {
 				return factoryBean.getObjectType();
@@ -151,8 +151,7 @@ public abstract class FactoryBeanRegistrySupport extends DefaultSingletonBeanReg
 			if (System.getSecurityManager() != null) {
 				AccessControlContext acc = getAccessControlContext();
 				try {
-					object = AccessController.doPrivileged((PrivilegedExceptionAction<Object>) () ->
-							factory.getObject(), acc);
+					object = AccessController.doPrivileged((PrivilegedExceptionAction<Object>) factory::getObject, acc);
 				}
 				catch (PrivilegedActionException pae) {
 					throw pae.getException();

spring-beans/src/main/java/org/springframework/beans/factory/support/SimpleInstantiationStrategy.java

@@ -72,7 +72,7 @@ public class SimpleInstantiationStrategy implements InstantiationStrategy {
 					try {
 						if (System.getSecurityManager() != null) {
 							constructorToUse = AccessController.doPrivileged(
-									(PrivilegedExceptionAction<Constructor<?>>) () -> clazz.getDeclaredConstructor());
+									(PrivilegedExceptionAction<Constructor<?>>) clazz::getDeclaredConstructor);
 						}
 						else {
 							constructorToUse =	clazz.getDeclaredConstructor();

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

@@ -24,6 +24,7 @@ import java.util.concurrent.CompletableFuture;
 import java.util.function.Function;
 
 import io.reactivex.BackpressureStrategy;
+import io.reactivex.Flowable;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -249,7 +250,7 @@ public class ReactiveAdapterRegistry {
 			registry.registerReactiveType(
 					multiValue(io.reactivex.Flowable.class, io.reactivex.Flowable::empty),
 					source -> (io.reactivex.Flowable<?>) source,
-					source-> io.reactivex.Flowable.fromPublisher(source)
+					Flowable::fromPublisher
 			);
 			registry.registerReactiveType(
 					multiValue(io.reactivex.Observable.class, io.reactivex.Observable::empty),

spring-core/src/main/java/org/springframework/core/convert/converter/ConvertingComparator.java

@@ -88,7 +88,7 @@ public class ConvertingComparator<S, T> implements Comparator<S> {
 	 * @return a new {@link ConvertingComparator} instance
 	 */
 	public static <K, V> ConvertingComparator<Map.Entry<K, V>, K> mapEntryKeys(Comparator<K> comparator) {
-		return new ConvertingComparator<>(comparator, source -> source.getKey());
+		return new ConvertingComparator<>(comparator, Map.Entry::getKey);
 	}
 
 	/**
@@ -98,7 +98,7 @@ public class ConvertingComparator<S, T> implements Comparator<S> {
 	 * @return a new {@link ConvertingComparator} instance
 	 */
 	public static <K, V> ConvertingComparator<Map.Entry<K, V>, V> mapEntryValues(Comparator<V> comparator) {
-		return new ConvertingComparator<>(comparator, source -> source.getValue());
+		return new ConvertingComparator<>(comparator, Map.Entry::getValue);
 	}
 
 

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

@@ -109,7 +109,7 @@ public class PropertyPlaceholderHelper {
 	 */
 	public String replacePlaceholders(String value, final Properties properties) {
 		Assert.notNull(properties, "'properties' must not be null");
-		return replacePlaceholders(value, placeholderName -> properties.getProperty(placeholderName));
+		return replacePlaceholders(value, properties::getProperty);
 	}
 
 	/**

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

@@ -583,7 +583,7 @@ public abstract class ReflectionUtils {
 	 */
 	public static Method[] getAllDeclaredMethods(Class<?> leafClass) {
 		final List<Method> methods = new ArrayList<>(32);
-		doWithMethods(leafClass, method -> methods.add(method));
+		doWithMethods(leafClass, methods::add);
 		return methods.toArray(new Method[methods.size()]);
 	}
 

spring-web/src/main/java/org/springframework/web/cors/reactive/UrlBasedCorsConfigurationSource.java

@@ -54,7 +54,7 @@ public class UrlBasedCorsConfigurationSource implements CorsConfigurationSource
 	public void setCorsConfigurations(@Nullable Map<String, CorsConfiguration> corsConfigurations) {
 		this.corsConfigurations.clear();
 		if (corsConfigurations != null) {
-			corsConfigurations.forEach((path, config) -> registerCorsConfiguration(path, config));
+			corsConfigurations.forEach(this::registerCorsConfiguration);
 		}
 	}
 

spring-webflux/src/main/java/org/springframework/web/reactive/config/WebFluxConfigurerComposite.java

@@ -18,6 +18,7 @@ package org.springframework.web.reactive.config;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -101,7 +102,7 @@ public class WebFluxConfigurerComposite implements WebFluxConfigurer {
 
 	@Nullable
 	private <T> T createSingleBean(Function<WebFluxConfigurer, T> factory, Class<T> beanType) {
-		List<T> result = this.delegates.stream().map(factory).filter(t -> t != null).collect(Collectors.toList());
+		List<T> result = this.delegates.stream().map(factory).filter(Objects::nonNull).collect(Collectors.toList());
 		if (result.isEmpty()) {
 			return null;
 		}