diff --git a/lib/delphi/src/Thrift.Protocol.JSON.pas b/lib/delphi/src/Thrift.Protocol.JSON.pas
index 71ee7ae..30600aa 100644
--- a/lib/delphi/src/Thrift.Protocol.JSON.pas
+++ b/lib/delphi/src/Thrift.Protocol.JSON.pas
@@ -103,7 +103,7 @@
 
       private
         FHasData : Boolean;
-        FData    : TBytes;
+        FData    : Byte;
 
       public
         // Return and consume the next byte to be Read, either taking it from the
@@ -169,18 +169,18 @@
 
   public
     // IProtocol
-    procedure WriteMessageBegin( const aMsg : IMessage); override;
+    procedure WriteMessageBegin( const aMsg : TThriftMessage); override;
     procedure WriteMessageEnd; override;
-    procedure WriteStructBegin( const struc: IStruct); override;
+    procedure WriteStructBegin( const struc: TThriftStruct); override;
     procedure WriteStructEnd; override;
-    procedure WriteFieldBegin( const field: IField); override;
+    procedure WriteFieldBegin( const field: TThriftField); override;
     procedure WriteFieldEnd; override;
     procedure WriteFieldStop; override;
-    procedure WriteMapBegin( const map: IMap); override;
+    procedure WriteMapBegin( const map: TThriftMap); override;
     procedure WriteMapEnd; override;
-    procedure WriteListBegin( const list: IList); override;
+    procedure WriteListBegin( const list: TThriftList); override;
     procedure WriteListEnd(); override;
-    procedure WriteSetBegin( const set_: ISet ); override;
+    procedure WriteSetBegin( const set_: TThriftSet ); override;
     procedure WriteSetEnd(); override;
     procedure WriteBool( b: Boolean); override;
     procedure WriteByte( b: ShortInt); override;
@@ -191,17 +191,17 @@
     procedure WriteString( const s: string );   override;
     procedure WriteBinary( const b: TBytes); override;
     //
-    function ReadMessageBegin: IMessage; override;
+    function ReadMessageBegin: TThriftMessage; override;
     procedure ReadMessageEnd(); override;
-    function ReadStructBegin: IStruct; override;
+    function ReadStructBegin: TThriftStruct; override;
     procedure ReadStructEnd; override;
-    function ReadFieldBegin: IField; override;
+    function ReadFieldBegin: TThriftField; override;
     procedure ReadFieldEnd(); override;
-    function ReadMapBegin: IMap; override;
+    function ReadMapBegin: TThriftMap; override;
     procedure ReadMapEnd(); override;
-    function ReadListBegin: IList; override;
+    function ReadListBegin: TThriftList; override;
     procedure ReadListEnd(); override;
-    function ReadSetBegin: ISet; override;
+    function ReadSetBegin: TThriftSet; override;
     procedure ReadSetEnd(); override;
     function ReadBool: Boolean; override;
     function ReadByte: ShortInt; override;
@@ -437,21 +437,19 @@
   if FHasData
   then FHasData := FALSE
   else begin
-    SetLength( FData, 1);
-    IJSONProtocol(FProto).Transport.ReadAll( FData, 0, 1);
+    IJSONProtocol(FProto).Transport.ReadAll( @FData, SizeOf(FData), 0, 1);
   end;
-  result := FData[0];
+  result := FData;
 end;
 
 
 function TJSONProtocolImpl.TLookaheadReader.Peek : Byte;
 begin
   if not FHasData then begin
-    SetLength( FData, 1);
-    IJSONProtocol(FProto).Transport.ReadAll( FData, 0, 1);
+    IJSONProtocol(FProto).Transport.ReadAll( @FData, SizeOf(FData), 0, 1);
     FHasData := TRUE;
   end;
-  result := FData[0];
+  result := FData;
 end;
 
 
@@ -681,7 +679,7 @@
 end;
 
 
-procedure TJSONProtocolImpl.WriteMessageBegin( const aMsg : IMessage);
+procedure TJSONProtocolImpl.WriteMessageBegin( const aMsg : TThriftMessage);
 begin
   ResetContextStack;  // THRIFT-1473
 
@@ -700,7 +698,7 @@
 end;
 
 
-procedure TJSONProtocolImpl.WriteStructBegin( const struc: IStruct);
+procedure TJSONProtocolImpl.WriteStructBegin( const struc: TThriftStruct);
 begin
   WriteJSONObjectStart;
 end;
@@ -712,7 +710,7 @@
 end;
 
 
-procedure TJSONProtocolImpl.WriteFieldBegin( const field : IField);
+procedure TJSONProtocolImpl.WriteFieldBegin( const field : TThriftField);
 begin
   WriteJSONInteger(field.ID);
   WriteJSONObjectStart;
@@ -731,7 +729,7 @@
   // nothing to do
 end;
 
-procedure TJSONProtocolImpl.WriteMapBegin( const map: IMap);
+procedure TJSONProtocolImpl.WriteMapBegin( const map: TThriftMap);
 begin
   WriteJSONArrayStart;
   WriteJSONString( GetTypeNameForTypeID( map.KeyType));
@@ -748,7 +746,7 @@
 end;
 
 
-procedure TJSONProtocolImpl.WriteListBegin( const list: IList);
+procedure TJSONProtocolImpl.WriteListBegin( const list: TThriftList);
 begin
   WriteJSONArrayStart;
   WriteJSONString( GetTypeNameForTypeID( list.ElementType));
@@ -762,7 +760,7 @@
 end;
 
 
-procedure TJSONProtocolImpl.WriteSetBegin( const set_: ISet);
+procedure TJSONProtocolImpl.WriteSetBegin( const set_: TThriftSet);
 begin
   WriteJSONArrayStart;
   WriteJSONString( GetTypeNameForTypeID( set_.ElementType));
@@ -1051,11 +1049,11 @@
 end;
 
 
-function TJSONProtocolImpl.ReadMessageBegin: IMessage;
+function TJSONProtocolImpl.ReadMessageBegin: TThriftMessage;
 begin
   ResetContextStack;  // THRIFT-1473
 
-  result := TMessageImpl.Create;
+  Init( result);
   ReadJSONArrayStart;
 
   if ReadJSONInteger <> VERSION
@@ -1073,10 +1071,10 @@
 end;
 
 
-function TJSONProtocolImpl.ReadStructBegin : IStruct ;
+function TJSONProtocolImpl.ReadStructBegin : TThriftStruct ;
 begin
   ReadJSONObjectStart;
-  result := TStructImpl.Create('');
+  Init( result);
 end;
 
 
@@ -1086,11 +1084,11 @@
 end;
 
 
-function TJSONProtocolImpl.ReadFieldBegin : IField;
+function TJSONProtocolImpl.ReadFieldBegin : TThriftField;
 var ch : Byte;
     str : string;
 begin
-  result := TFieldImpl.Create;
+  Init( result);
   ch := FReader.Peek;
   if ch = RBRACE[0]
   then result.Type_ := TType.Stop
@@ -1110,10 +1108,10 @@
 end;
 
 
-function TJSONProtocolImpl.ReadMapBegin : IMap;
+function TJSONProtocolImpl.ReadMapBegin : TThriftMap;
 var str : string;
 begin
-  result := TMapImpl.Create;
+  Init( result);
   ReadJSONArrayStart;
 
   str := SysUtils.TEncoding.UTF8.GetString( ReadJSONString(FALSE));
@@ -1134,10 +1132,10 @@
 end;
 
 
-function TJSONProtocolImpl.ReadListBegin : IList;
+function TJSONProtocolImpl.ReadListBegin : TThriftList;
 var str : string;
 begin
-  result := TListImpl.Create;
+  Init( result);
   ReadJSONArrayStart;
 
   str := SysUtils.TEncoding.UTF8.GetString( ReadJSONString(FALSE));
@@ -1152,10 +1150,10 @@
 end;
 
 
-function TJSONProtocolImpl.ReadSetBegin : ISet;
+function TJSONProtocolImpl.ReadSetBegin : TThriftSet;
 var str : string;
 begin
-  result := TSetImpl.Create;
+  Init( result);
   ReadJSONArrayStart;
 
   str := SysUtils.TEncoding.UTF8.GetString( ReadJSONString(FALSE));