diff --git a/spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java b/spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java
index cfb3fd813670..56c894fa0501 100644
--- a/spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java
+++ b/spring-core/src/main/java/org/springframework/core/env/AbstractEnvironment.java
@@ -469,9 +469,7 @@ public void merge(ConfigurableEnvironment parent) {
 		if (!ObjectUtils.isEmpty(parentDefaultProfiles)) {
 			synchronized (this.defaultProfiles) {
 				this.defaultProfiles.remove(RESERVED_DEFAULT_PROFILE_NAME);
-				for (String profile : parentDefaultProfiles) {
-					this.defaultProfiles.add(profile);
-				}
+				Collections.addAll(this.defaultProfiles, parentDefaultProfiles);
 			}
 		}
 	}