Java full runtime: Avoid allocating when calling asMap on empty Unkno…

…wnFieldSet PiperOrigin-RevId: 631235442
protocolbuffers · May 7, 2024 · d0b016f · d0b016f
1 parent f597991
commit d0b016f
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java b/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java
@@ -85,6 +85,10 @@ public int hashCode() {
 
   /** Get a map of fields in the set by number. */
   public Map<Integer, Field> asMap() {
+    // Avoid an allocation for the common case of an empty map.
+    if (fields.isEmpty()) {
+      return Collections.emptyMap();
+    }
     return (Map<Integer, Field>) fields.clone();
   }