Polish lambda expression and method reference

See gh-49023

Signed-off-by: Yanming Zhou <zhouyanming@gmail.com>

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/prometheus/PrometheusPushGatewayManager.java

@@ -160,7 +160,7 @@ public class PrometheusPushGatewayManager {
 
 		@Override
 		public ScheduledExecutorService getScheduledExecutor() throws IllegalStateException {
-			return Executors.newSingleThreadScheduledExecutor(this::newThread);
+			return Executors.newSingleThreadScheduledExecutor(this);
 		}
 
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/AutoConfigurations.java

@@ -58,7 +58,7 @@ public class AutoConfigurations extends Configurations implements Ordered {
 	private static UnaryOperator<Collection<Class<?>>> sorter(UnaryOperator<String> replacementMapper) {
 		AutoConfigurationSorter sorter = new AutoConfigurationSorter(metadataReaderFactory, null, replacementMapper);
 		return (classes) -> {
-			List<String> names = classes.stream().map(Class::getName).map(replacementMapper::apply).toList();
+			List<String> names = classes.stream().map(Class::getName).map(replacementMapper).toList();
 			List<String> sorted = sorter.getInPriorityOrder(names);
 			return sorted.stream()
 				.map((className) -> ClassUtils.resolveClassName(className, null))

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/logging/log4j2/SpringBootPropertySource.java

@@ -39,7 +39,7 @@ public class SpringBootPropertySource implements PropertySource {
 
 	@Override
 	public void forEach(BiConsumer<String, String> action) {
-		this.properties.forEach(action::accept);
+		this.properties.forEach(action);
 	}
 
 	@Override