Polish

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/web/exchanges/InMemoryHttpExchangeRepository.java

@@ -16,8 +16,6 @@
 
 package org.springframework.boot.actuate.web.exchanges;
 
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -59,7 +57,7 @@ public class InMemoryHttpExchangeRepository implements HttpExchangeRepository {
 	@Override
 	public List<HttpExchange> findAll() {
 		synchronized (this.httpExchanges) {
-			return Collections.unmodifiableList(new ArrayList<>(this.httpExchanges));
+			return List.copyOf(this.httpExchanges);
 		}
 	}
 

spring-boot-project/spring-boot-testcontainers/src/main/java/org/springframework/boot/testcontainers/lifecycle/TestcontainersLifecycleApplicationContextInitializer.java

@@ -36,7 +36,7 @@ import org.springframework.context.ConfigurableApplicationContext;
 public class TestcontainersLifecycleApplicationContextInitializer
 		implements ApplicationContextInitializer<ConfigurableApplicationContext> {
 
-	private static Set<ConfigurableApplicationContext> applied = Collections.newSetFromMap(new WeakHashMap<>());
+	private static final Set<ConfigurableApplicationContext> applied = Collections.newSetFromMap(new WeakHashMap<>());
 
 	@Override
 	public void initialize(ConfigurableApplicationContext applicationContext) {