【.NET2003 Windows】シングルトンクラス　と　静的メソッド　の違い

コード�@
NotInheritable Public Class Singleton
   Private Shared instance As New Singleton()
   Private Shared_Data As String
   
   Private Sub New()
   End Sub  
   
   Public Shared ReadOnly Property Instance() As Singleton
      Get
         Return instance
      End Get
   End Property
   
   Public Property [Shared_Data] As String
      Get
         Return Shared_Data
      End Get
      Set(ByVal in_Data As String)
         Shared_Data = in_Data
      End Set
   End Property
End Class 

コード�A
NotInheritable Public Class Seiteki
   Private Shared Shared_Data As String
   
   Public Shared Property [Shared_Data] As String
      Get
         Return Shared_Data
      End Get
      Set(ByVal in_Data As String)
         Shared_Data = in_Data
      End Set
   End Property
   
End Class