instances := TStringList.Create;
........
class function TLogger.GetInstance(const AName : String) : TLogger;
var
   index : Integer;
   logger : TLogger;
begin
   index := Instances.IndexOf(AName);
   if (index < 0) then begin
      logger := TLogger.Create(AName);
      instances.AddObject(AName, logger);
      Result := logger;
   end else
   Result := TLogger(instances.Objects[index]);
end;

procedure TWriterAppender.Append(AEvent : TLoggingEvent);
begin
   if (Self.FClosed) then begin
      if (Self.FErrorHandler <> Nil) then
         Self.FErrorHandler.Error(
            'This appender is closed and cannot be written to.');
      Exit;
   end;
   Self.FWriter.Println(Self.Flayout.Format(AEvent));
   if not (Self.Flayout.IgnoresException) then
      if (AEvent.getException <> Nil) then
         Self.FWriter.Println('Exception: ' + AEvent.GetException.Message);
end;

procedure TPrintWriter.Print(AMsg : String);
begin
  if (AMsg <> '') then
    // See http://sourceforge.net/projects/log4delphi/forums/forum/486124/topic/3270609
    {$IFDEF UNICODE}
      FStream.Write(PAnsiChar(UTF8String(AMsg))^, Length(UTF8String(AMsg)));
    {$ELSE}
      FStream.Write(PChar(AMsg)^, Length(AMsg));
    {$ENDIF}
end;