@@ -137,21 +137,22 @@
 {
 }
 
 - (void)dealloc
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 	[super dealloc];	/* Get rid of a stupid warning */
 }
 @end
 
 @implementation OFMutableArray
 + (void)initialize
 {
 	if (self == [OFMutableArray class])
-		placeholder.isa = [OFMutableArray_placeholder class];
+		object_setClass((id)&placeholder,
+		    [OFMutableArray_placeholder class]);
 }
 
 + alloc
 {
 	if (self == [OFMutableArray class])
@@ -160,12 +161,12 @@
 	return [super alloc];
 }
 
 - init
 {
-	if (isa == [OFMutableArray class]) {
-		Class c = isa;
+	if (object_getClass(self) == [OFMutableArray class]) {
+		Class c = [self class];
 		[self release];
 		@throw [OFNotImplementedException exceptionWithClass: c
 							    selector: _cmd];
 	}
 
@@ -190,11 +191,11 @@
 }
 
 - (void)insertObject: (id)object
 	     atIndex: (size_t)index
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 }
 
 - (void)insertObjectsFromArray: (OFArray*)array
 		       atIndex: (size_t)index
@@ -216,11 +217,11 @@
 }
 
 - (void)replaceObjectAtIndex: (size_t)index
 		  withObject: (id)object
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 }
 
 -    (void)setObject: (id)object
   atIndexedSubscript: (size_t)index
@@ -258,11 +259,11 @@
 	}
 }
 
 - (void)removeObjectAtIndex: (size_t)index
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 }
 
 - (void)removeObject: (id)object
 {