讨论下delphi里的静态方法

以前只知道delphi解决静态函数的方法是在函数前加class
我也一直深信static不能是 override virtual abstract，但是今天看到一个帖子，突然头大了

http://topic.csdn.net/u/20110827/16/cf1b0a13-7f55-4201-af6c-7dbc0c3da93d.html

帖子中的代码如下 
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
  Button1: TButton;
  procedure Button1Click(Sender: TObject);
  private
  { Private declarations }
  public
  { Public declarations }
  end;

  TBaseClass = class
  public
  class procedure ClassFun; virtual;
  end;

  TBClass2 = class(TBaseClass)
  public
  class procedure ClassFun; override;
  end;

  TBClass3 = class(TBaseClass)
  public
  class procedure ClassFun; override;
  end;

  TClassRef = class of TBaseClass;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  c: TClassRef;
begin
  ShowMessage('Call TBClass2 >>>');
  c := TBClass2;
  c.ClassFun;
  //TBClass2.ClassFun;

  ShowMessage('Call TBClass3 >>>');
  c := TBClass3;
  c.ClassFun;
end;

{ TBaseClass }

class procedure TBaseClass.ClassFun;
begin
  ShowMessage('TBaseClass');
end;

{ TBClass2 }

class procedure TBClass2.ClassFun;
begin
  inherited;
  ShowMessage('TBClass2');
end;

{ TBClass3 }

class procedure TBClass3.ClassFun;
begin
  inherited;
  ShowMessage('TBClass3');
end;

end.

以上代码看过之后糊涂了，有人能帮忙解释一下么？为啥delphi里的class静态机制可以是virtual和override甚至是abstract的？

加class好像是类方法，好像不关静态的事。

delphi里实现类的静态方法就是在方法前加入class啊