diff --git a/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java b/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
index 6d72e89e3c..af1ca45604 100644
--- a/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
+++ b/spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java
@@ -231,11 +231,7 @@ class ConfigurationClassParser {
 				// Explicit bean definition found, probably replacing an import.
 				// Let's remove the old one and go with the new one.
 				this.configurationClasses.remove(configClass);
-				for (Iterator<ConfigurationClass> it = this.knownSuperclasses.values().iterator(); it.hasNext();) {
-					if (configClass.equals(it.next())) {
-						it.remove();
-					}
-				}
+				this.knownSuperclasses.values().removeIf(configClass::equals);
 			}
 		}
 
diff --git a/spring-core/src/main/java/org/springframework/core/ReactiveAdapterRegistry.java b/spring-core/src/main/java/org/springframework/core/ReactiveAdapterRegistry.java
index 415df656c0..a05aff87ab 100644
--- a/spring-core/src/main/java/org/springframework/core/ReactiveAdapterRegistry.java
+++ b/spring-core/src/main/java/org/springframework/core/ReactiveAdapterRegistry.java
@@ -104,31 +104,6 @@ public class ReactiveAdapterRegistry {
 	}
 
 
-	/**
-	 * Return a shared default {@code ReactiveAdapterRegistry} instance, lazily
-	 * building it once needed.
-	 * <p><b>NOTE:</b> We highly recommend passing a long-lived, pre-configured
-	 * {@code ReactiveAdapterRegistry} instance for customization purposes.
-	 * This accessor is only meant as a fallback for code paths that want to
-	 * fall back on a default instance if one isn't provided.
-	 * @return the shared {@code ReactiveAdapterRegistry} instance (never {@code null})
-	 * @since 5.0.2
-	 */
-	public static ReactiveAdapterRegistry getSharedInstance() {
-		ReactiveAdapterRegistry ar = sharedInstance;
-		if (ar == null) {
-			synchronized (ReactiveAdapterRegistry.class) {
-				ar = sharedInstance;
-				if (ar == null) {
-					ar = new ReactiveAdapterRegistry();
-					sharedInstance = ar;
-				}
-			}
-		}
-		return ar;
-	}
-
-
 	/**
 	 * Whether the registry has any adapters which would be the case if any of
 	 * Reactor, RxJava 2, or RxJava 1 (+ RxJava Reactive Streams bridge) are
@@ -138,7 +113,6 @@ public class ReactiveAdapterRegistry {
 		return !this.adapters.isEmpty();
 	}
 
-
 	/**
 	 * Register a reactive type along with functions to adapt to and from a
 	 * Reactive Streams {@link Publisher}. The functions can assume their
@@ -190,6 +164,31 @@ public class ReactiveAdapterRegistry {
 	}
 
 
+	/**
+	 * Return a shared default {@code ReactiveAdapterRegistry} instance, lazily
+	 * building it once needed.
+	 * <p><b>NOTE:</b> We highly recommend passing a long-lived, pre-configured
+	 * {@code ReactiveAdapterRegistry} instance for customization purposes.
+	 * This accessor is only meant as a fallback for code paths that want to
+	 * fall back on a default instance if one isn't provided.
+	 * @return the shared {@code ReactiveAdapterRegistry} instance (never {@code null})
+	 * @since 5.0.2
+	 */
+	public static ReactiveAdapterRegistry getSharedInstance() {
+		ReactiveAdapterRegistry ar = sharedInstance;
+		if (ar == null) {
+			synchronized (ReactiveAdapterRegistry.class) {
+				ar = sharedInstance;
+				if (ar == null) {
+					ar = new ReactiveAdapterRegistry();
+					sharedInstance = ar;
+				}
+			}
+		}
+		return ar;
+	}
+
+
 	private static class ReactorRegistrar {
 
 		void registerAdapters(ReactiveAdapterRegistry registry) {
diff --git a/spring-core/src/main/java/org/springframework/core/convert/support/DefaultConversionService.java b/spring-core/src/main/java/org/springframework/core/convert/support/DefaultConversionService.java
index 101f99b44a..e9797987c4 100644
--- a/spring-core/src/main/java/org/springframework/core/convert/support/DefaultConversionService.java
+++ b/spring-core/src/main/java/org/springframework/core/convert/support/DefaultConversionService.java
@@ -44,6 +44,15 @@ public class DefaultConversionService extends GenericConversionService {
 	private static volatile DefaultConversionService sharedInstance;
 
 
+	/**
+	 * Create a new {@code DefaultConversionService} with the set of
+	 * {@linkplain DefaultConversionService#addDefaultConverters(ConverterRegistry) default converters}.
+	 */
+	public DefaultConversionService() {
+		addDefaultConverters(this);
+	}
+
+
 	/**
 	 * Return a shared default {@code ConversionService} instance,
 	 * lazily building it once needed.
@@ -69,18 +78,6 @@ public class DefaultConversionService extends GenericConversionService {
 		return cs;
 	}
 
-
-	/**
-	 * Create a new {@code DefaultConversionService} with the set of
-	 * {@linkplain DefaultConversionService#addDefaultConverters(ConverterRegistry) default converters}.
-	 */
-	public DefaultConversionService() {
-		addDefaultConverters(this);
-	}
-
-
-	// static utility methods
-
 	/**
 	 * Add converters appropriate for most environments.
 	 * @param converterRegistry the registry of converters to add to (must also be castable to ConversionService,
@@ -134,9 +131,6 @@ public class DefaultConversionService extends GenericConversionService {
 		converterRegistry.addConverter(new StreamConverter(conversionService));
 	}
 
-
-	// internal helpers
-
 	private static void addScalarConverters(ConverterRegistry converterRegistry) {
 		converterRegistry.addConverterFactory(new NumberToNumberConverterFactory());