@@ -93,21 +93,21 @@
 {
 }
 
 - (void)dealloc
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 	[super dealloc];	/* Get rid of a stupid warning */
 }
 @end
 
 @implementation OFSet
 + (void)initialize
 {
 	if (self == [OFSet class])
-		placeholder.isa = [OFSet_placeholder class];
+		object_setClass((id)&placeholder, [OFSet_placeholder class]);
 }
 
 + alloc
 {
 	if (self == [OFSet class])
@@ -151,12 +151,12 @@
 					count: count] autorelease];
 }
 
 - init
 {
-	if (isa == [OFSet class]) {
-		Class c = isa;
+	if (object_getClass(self) == [OFSet class]) {
+		Class c = [self class];
 		[self release];
 		@throw [OFNotImplementedException exceptionWithClass: c
 							    selector: _cmd];
 	}
 
@@ -163,19 +163,19 @@
 	return [super init];
 }
 
 - initWithSet: (OFSet*)set
 {
-	Class c = isa;
+	Class c = [self class];
 	[self release];
 	@throw [OFNotImplementedException exceptionWithClass: c
 						    selector: _cmd];
 }
 
 - initWithArray: (OFArray*)array
 {
-	Class c = isa;
+	Class c = [self class];
 	[self release];
 	@throw [OFNotImplementedException exceptionWithClass: c
 						    selector: _cmd];
 }
 
@@ -193,56 +193,56 @@
 }
 
 - initWithObjects: (id const*)objects
 	    count: (size_t)count
 {
-	Class c = isa;
+	Class c = [self class];
 	[self release];
 	@throw [OFNotImplementedException exceptionWithClass: c
 						    selector: _cmd];
 }
 
 - initWithObject: (id)firstObject
        arguments: (va_list)arguments
 {
-	Class c = isa;
+	Class c = [self class];
 	[self release];
 	@throw [OFNotImplementedException exceptionWithClass: c
 						    selector: _cmd];
 }
 
 - initWithSerialization: (OFXMLElement*)element
 {
-	Class c = isa;
+	Class c = [self class];
 	[self release];
 	@throw [OFNotImplementedException exceptionWithClass: c
 						    selector: _cmd];
 }
 
 - (size_t)count
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 }
 
 - (BOOL)containsObject: (id)object
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 }
 
 - (OFEnumerator*)objectEnumerator
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 }
 
 - (int)countByEnumeratingWithState: (of_fast_enumeration_state_t*)state
 			   objects: (id*)objects
 			     count: (int)count
 {
-	@throw [OFNotImplementedException exceptionWithClass: isa
+	@throw [OFNotImplementedException exceptionWithClass: [self class]
 						    selector: _cmd];
 }
 
 - (BOOL)isEqual: (id)object
 {