Pop quiz #1

What could be wrong with this class?  Think carefully and post your answer in the comments. 

 

class Something
{
      public string ServiceName { get; private set; }
      public int DbId { get; private set; } 

      public Something(string serviceName, int dbId)
      {
            if (serviceName == null) throw new ArgumentNullException("serviceName");
            ServiceName = serviceName;
            DbId = dbId;
      } 

      public override int GetHashCode()
      {
            return ServiceName.GetHashCode() + DbId;
      } 

      public override bool Equals(object obj)
      {
            Something other = obj as Something;
            return other != null && DbId == other.DbId && ServiceName == other.ServiceName;
      }
}