diff --git a/JSONKit.m b/JSONKit.m
index 0e9331f..4994caf 100644
--- a/JSONKit.m
+++ b/JSONKit.m
@@ -677,7 +677,7 @@ + (id)allocWithZone:(NSZone *)zone
   NSCParameterAssert((objects != NULL) && (_JKArrayClass != NULL) && (_JKArrayInstanceSize > 0UL));
   JKArray *array = NULL;
   if(JK_EXPECT_T((array = (JKArray *)calloc(1UL, _JKArrayInstanceSize)) != NULL)) { // Directly allocate the JKArray instance via calloc.
-    array->isa      = _JKArrayClass;
+    object_setClass(array, _JKArrayClass);
     if((array = [array init]) == NULL) { return(NULL); }
     array->capacity = count;
     array->count    = count;
@@ -928,7 +928,7 @@ static void _JKDictionaryResizeIfNeccessary(JKDictionary *dictionary) {
   NSCParameterAssert((keys != NULL) && (keyHashes != NULL) && (objects != NULL) && (_JKDictionaryClass != NULL) && (_JKDictionaryInstanceSize > 0UL));
   JKDictionary *dictionary = NULL;
   if(JK_EXPECT_T((dictionary = (JKDictionary *)calloc(1UL, _JKDictionaryInstanceSize)) != NULL)) { // Directly allocate the JKDictionary instance via calloc.
-    dictionary->isa      = _JKDictionaryClass;
+    object_setClass(dictionary, _JKDictionaryClass);
     if((dictionary = [dictionary init]) == NULL) { return(NULL); }
     dictionary->capacity = _JKDictionaryCapacityForCount(count);
     dictionary->count    = 0UL;