diff --git a/spring-cloud-kubernetes-client-config/src/main/java/org/springframework/cloud/kubernetes/client/config/KubernetesClientSecretsPropertySource.java b/spring-cloud-kubernetes-client-config/src/main/java/org/springframework/cloud/kubernetes/client/config/KubernetesClientSecretsPropertySource.java
index 642386f604..bac7a39fe5 100644
--- a/spring-cloud-kubernetes-client-config/src/main/java/org/springframework/cloud/kubernetes/client/config/KubernetesClientSecretsPropertySource.java
+++ b/spring-cloud-kubernetes-client-config/src/main/java/org/springframework/cloud/kubernetes/client/config/KubernetesClientSecretsPropertySource.java
@@ -29,6 +29,7 @@
  */
 public class KubernetesClientSecretsPropertySource extends SecretsPropertySource {
 
+	@Deprecated(forRemoval = true)
 	public KubernetesClientSecretsPropertySource(SourceData sourceData) {
 		super(sourceData);
 	}
diff --git a/spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/src/main/java/org/springframework/cloud/kubernetes/configserver/KubernetesEnvironmentRepository.java b/spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/src/main/java/org/springframework/cloud/kubernetes/configserver/KubernetesEnvironmentRepository.java
index 3c25e7f91b..aa377751d4 100644
--- a/spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/src/main/java/org/springframework/cloud/kubernetes/configserver/KubernetesEnvironmentRepository.java
+++ b/spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/src/main/java/org/springframework/cloud/kubernetes/configserver/KubernetesEnvironmentRepository.java
@@ -16,9 +16,8 @@
 
 package org.springframework.cloud.kubernetes.configserver;
 
-import java.util.Arrays;
+import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -41,11 +40,11 @@ public class KubernetesEnvironmentRepository implements EnvironmentRepository {
 
 	private static final Log LOG = LogFactory.getLog(KubernetesEnvironmentRepository.class);
 
-	private CoreV1Api coreApi;
+	private final CoreV1Api coreApi;
 
-	private List<KubernetesPropertySourceSupplier> kubernetesPropertySourceSuppliers;
+	private final List<KubernetesPropertySourceSupplier> kubernetesPropertySourceSuppliers;
 
-	private String namespace;
+	private final String namespace;
 
 	public KubernetesEnvironmentRepository(CoreV1Api coreApi,
 			List<KubernetesPropertySourceSupplier> kubernetesPropertySourceSuppliers, String namespace) {
@@ -64,8 +63,7 @@ public Environment findOne(String application, String profile, String label, boo
 		if (!StringUtils.hasText(profile)) {
 			profile = "default";
 		}
-		List<String> profiles = new java.util.ArrayList<>(
-				Arrays.stream(StringUtils.commaDelimitedListToStringArray(profile)).toList());
+		List<String> profiles = new ArrayList<>(List.of(StringUtils.commaDelimitedListToStringArray(profile)));
 
 		Collections.reverse(profiles);
 		if (!profiles.contains("default")) {
@@ -98,8 +96,7 @@ public Environment findOne(String application, String profile, String label, boo
 	}
 
 	private MutablePropertySources createPropertySources(String application) {
-		Map<String, Object> applicationProperties = new HashMap<>();
-		applicationProperties.put("spring.application.name", application);
+		Map<String, Object> applicationProperties = Map.of("spring.application.name", application);
 		MapPropertySource propertySource = new MapPropertySource("kubernetes-config-server", applicationProperties);
 		MutablePropertySources mutablePropertySources = new MutablePropertySources();
 		mutablePropertySources.addFirst(propertySource);
@@ -108,7 +105,7 @@ private MutablePropertySources createPropertySources(String application) {
 
 	private void addApplicationConfiguration(Environment environment, StandardEnvironment springEnv,
 			String applicationName) {
-		kubernetesPropertySourceSuppliers.stream().forEach(supplier -> {
+		kubernetesPropertySourceSuppliers.forEach(supplier -> {
 			List<MapPropertySource> propertySources = supplier.get(coreApi, applicationName, namespace, springEnv);
 			propertySources.forEach(propertySource -> {
 				if (propertySource.getPropertyNames().length > 0) {
diff --git a/spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/src/main/java/org/springframework/cloud/kubernetes/configserver/KubernetesPropertySourceSupplier.java b/spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/src/main/java/org/springframework/cloud/kubernetes/configserver/KubernetesPropertySourceSupplier.java
index a73af430dd..e2973ac2e6 100644
--- a/spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/src/main/java/org/springframework/cloud/kubernetes/configserver/KubernetesPropertySourceSupplier.java
+++ b/spring-cloud-kubernetes-controllers/spring-cloud-kubernetes-configserver/src/main/java/org/springframework/cloud/kubernetes/configserver/KubernetesPropertySourceSupplier.java
@@ -16,8 +16,6 @@
 
 package org.springframework.cloud.kubernetes.configserver;
 
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 
 import io.kubernetes.client.openapi.apis.CoreV1Api;
@@ -33,11 +31,18 @@ public interface KubernetesPropertySourceSupplier {
 
 	List<MapPropertySource> get(CoreV1Api coreV1Api, String name, String namespace, Environment environment);
 
+	/*
+	 * return either a List containing 'currentNamespace' (if 'namespacesString' is empty
+	 * or null), or a List of comma delimited tokens (namespaces) from 'namespacesString'.
+	 *
+	 * 'currentNamespace' can be treated logically as the "default namespace" to use, if
+	 * the other argument is not provided.
+	 */
 	static List<String> namespaceSplitter(String namespacesString, String currentNamespace) {
-		List<String> namespaces = Collections.singletonList(currentNamespace);
+		List<String> namespaces = List.of(currentNamespace);
 		String[] namespacesArray = StringUtils.commaDelimitedListToStringArray(namespacesString);
 		if (namespacesArray.length > 0) {
-			namespaces = Arrays.asList(namespacesArray);
+			namespaces = List.of(namespacesArray);
 		}
 		return namespaces;
 	}