Index: src/SSLInvalidCertificateException.m
==================================================================
--- src/SSLInvalidCertificateException.m
+++ src/SSLInvalidCertificateException.m
@@ -32,11 +32,11 @@
 				     reason: reason_] autorelease];
 }
 
 - initWithClass: (Class)class_
 {
-	Class c = isa;
+	Class c = [self class];
 	[self release];
 	@throw [OFNotImplementedException exceptionWithClass: c
 						    selector: _cmd];
 }
 

Index: src/SSLSocket.m
==================================================================
--- src/SSLSocket.m
+++ src/SSLSocket.m
@@ -129,11 +129,11 @@
 
 		if ((ssl = SSL_new(ctx)) == NULL || !SSL_set_fd(ssl, sock)) {
 			close(sock);
 			sock = INVALID_SOCKET;
 			@throw [OFInitializationFailedException
-			    exceptionWithClass: isa];
+			    exceptionWithClass: [self class]];
 		}
 
 		SSL_set_connect_state(ssl);
 
 		if ((privateKeyFile != nil && !SSL_use_PrivateKey_file(ssl,
@@ -144,11 +144,11 @@
 		    OF_STRING_ENCODING_NATIVE], SSL_FILETYPE_PEM)) ||
 		    SSL_connect(ssl) != 1) {
 			close(sock);
 			sock = INVALID_SOCKET;
 			@throw [OFInitializationFailedException
-			    exceptionWithClass: isa];
+			    exceptionWithClass: [self class]];
 		}
 	} @catch (id e) {
 		[self release];
 		@throw e;
 	}
@@ -175,14 +175,15 @@
 	[super connectToHost: host
 			port: port];
 
 	if ((ssl = SSL_new(ctx)) == NULL || !SSL_set_fd(ssl, sock)) {
 		[super close];
-		@throw [OFConnectionFailedException exceptionWithClass: isa
-								socket: self
-								  host: host
-								  port: port];
+		@throw [OFConnectionFailedException
+		    exceptionWithClass: [self class]
+				socket: self
+				  host: host
+				  port: port];
 	}
 
 	SSL_set_connect_state(ssl);
 
 	if ((privateKeyFile != nil && !SSL_use_PrivateKey_file(ssl,
@@ -190,14 +191,15 @@
 	    SSL_FILETYPE_PEM)) || (certificateFile != nil &&
 	    !SSL_use_certificate_file(ssl, [certificateFile
 	    cStringWithEncoding: OF_STRING_ENCODING_NATIVE],
 	    SSL_FILETYPE_PEM)) || SSL_connect(ssl) != 1) {
 		[super close];
-		@throw [OFConnectionFailedException exceptionWithClass: isa
-								socket: self
-								  host: host
-								  port: port];
+		@throw [OFConnectionFailedException
+		    exceptionWithClass: [self class]
+				socket: self
+				  host: host
+				  port: port];
 	}
 }
 
 - (SSLSocket*)accept
 {
@@ -204,15 +206,15 @@
 	SSLSocket *newSocket = (SSLSocket*)[super accept];
 
 	if ((newSocket->ssl = SSL_new(ctx)) == NULL ||
 	    !SSL_set_fd(newSocket->ssl, newSocket->sock)) {
 		/* We only want to close the OFTCPSocket */
-		newSocket->isa = [OFTCPSocket class];
+		object_setClass(newSocket, [OFTCPSocket class]);
 		[newSocket close];
-		newSocket->isa = isa;
+		object_setClass(newSocket, object_getClass(self));
 
-		@throw [OFAcceptFailedException exceptionWithClass: isa
+		@throw [OFAcceptFailedException exceptionWithClass: [self class]
 							    socket: self];
 	}
 
 	SSL_set_accept_state(newSocket->ssl);
 
@@ -220,15 +222,15 @@
 	    cStringWithEncoding: OF_STRING_ENCODING_NATIVE],
 	    SSL_FILETYPE_PEM) || !SSL_use_certificate_file(newSocket->ssl,
 	    [certificateFile cStringWithEncoding: OF_STRING_ENCODING_NATIVE],
 	    SSL_FILETYPE_PEM) || SSL_accept(newSocket->ssl) != 1) {
 		/* We only want to close the OFTCPSocket */
-		newSocket->isa = [OFTCPSocket class];
+		object_setClass(newSocket, [OFTCPSocket class]);
 		[newSocket close];
-		newSocket->isa = isa;
+		object_setClass(newSocket, object_getClass(self));
 
-		@throw [OFAcceptFailedException exceptionWithClass: isa
+		@throw [OFAcceptFailedException exceptionWithClass: [self class]
 							    socket: self];
 	}
 
 	return newSocket;
 }
@@ -245,20 +247,20 @@
 		   length: (size_t)length
 {
 	ssize_t ret;
 
 	if (length > INT_MAX)
-		@throw [OFOutOfRangeException exceptionWithClass: isa];
+		@throw [OFOutOfRangeException exceptionWithClass: [self class]];
 
 	if (sock == INVALID_SOCKET)
-		@throw [OFNotConnectedException exceptionWithClass: isa
+		@throw [OFNotConnectedException exceptionWithClass: [self class]
 							    socket: self];
 
 	if (atEndOfStream) {
 		OFReadFailedException *e;
 
-		e = [OFReadFailedException exceptionWithClass: isa
+		e = [OFReadFailedException exceptionWithClass: [self class]
 						       stream: self
 					      requestedLength: length];
 #ifndef _WIN32
 		e->errNo = ENOTCONN;
 #else
@@ -267,11 +269,11 @@
 
 		@throw e;
 	}
 
 	if ((ret = SSL_read(ssl, buffer, (int)length)) < 0)
-		@throw [OFReadFailedException exceptionWithClass: isa
+		@throw [OFReadFailedException exceptionWithClass: [self class]
 							  stream: self
 						 requestedLength: length];
 
 	if (ret == 0)
 		atEndOfStream = YES;
@@ -281,20 +283,20 @@
 
 - (void)_writeBuffer: (const void*)buffer
 	      length: (size_t)length
 {
 	if (length > INT_MAX)
-		@throw [OFOutOfRangeException exceptionWithClass: isa];
+		@throw [OFOutOfRangeException exceptionWithClass: [self class]];
 
 	if (sock == INVALID_SOCKET)
-		@throw [OFNotConnectedException exceptionWithClass: isa
+		@throw [OFNotConnectedException exceptionWithClass: [self class]
 							    socket: self];
 
 	if (atEndOfStream) {
 		OFWriteFailedException *e;
 
-		e = [OFWriteFailedException exceptionWithClass: isa
+		e = [OFWriteFailedException exceptionWithClass: [self class]
 							stream: self
 					 requestedLength: length];
 
 #ifndef _WIN32
 		e->errNo = ENOTCONN;
@@ -304,11 +306,11 @@
 
 		@throw e;
 	}
 
 	if (SSL_write(ssl, buffer, (int)length) < length)
-		@throw [OFWriteFailedException exceptionWithClass: isa
+		@throw [OFWriteFailedException exceptionWithClass: [self class]
 							   stream: self
 						  requestedLength: length];
 }
 
 - (size_t)pendingBytes
@@ -344,12 +346,13 @@
 	size_t length;
 	char buffer[64];
 	OFDataArray *data;
 
 	if (![type isEqual: @"tls-unique"])
-		@throw [OFInvalidArgumentException exceptionWithClass: isa
-							     selector: _cmd];
+		@throw [OFInvalidArgumentException
+		    exceptionWithClass: [self class]
+			      selector: _cmd];
 
 	if (SSL_session_reused(ssl) ^ !listening) {
 		/*
 		 * We are either client or the session has been resumed
 		 * => we have sent the finished message
@@ -384,11 +387,11 @@
 
 	if ((SSL_get_peer_certificate(ssl) == NULL) ||
 	    ((ret = SSL_get_verify_result(ssl)) != X509_V_OK)) {
 		const char *reason = X509_verify_cert_error_string(ret);
 		@throw [SSLInvalidCertificateException
-			exceptionWithClass: isa
+			exceptionWithClass: [self class]
 				    reason: [OFString
 						stringWithUTF8String: reason]];
 	}
 }
 @end

Index: src/X509Certificate.m
==================================================================
--- src/X509Certificate.m
+++ src/X509Certificate.m
@@ -51,11 +51,11 @@
 		const unsigned char *dataCArray = [data cArray];
 		crt = d2i_X509(NULL, &dataCArray, [data count]);
 		[pool release];
 		if (crt == NULL)
 			@throw [OFInitializationFailedException
-				    exceptionWithClass: isa];
+				    exceptionWithClass: [self class]];
 	} @catch (id e) {
 		[self release];
 		@throw e;
 	}
 
@@ -68,11 +68,11 @@
 
 	@try {
 		crt = X509_dup(cert);
 		if (crt == NULL)
 			@throw [OFInitializationFailedException
-				    exceptionWithClass: isa];
+				    exceptionWithClass: [self class]];
 	} @catch (id e) {
 		[self release];
 		@throw e;
 	}
 
@@ -416,11 +416,12 @@
 {
 	OFString *ret;
 	char *buffer;
 
 	if (ASN1_STRING_to_UTF8((unsigned char**)&buffer, str) < 0)
-		@throw [OFInvalidEncodingException exceptionWithClass: isa];
+		@throw [OFInvalidEncodingException
+		    exceptionWithClass: [self class]];
 
 	@try {
 		ret = [OFString stringWithUTF8String: buffer];
 	} @finally {
 		OPENSSL_free(buffer);