DefaultTableColumn spec contains references to the condition: if selectionModel is null. They are following:

getSelectionModel():
    "Or null if row selection is not allowed."
getSelectedColumns:
    "If selectionModel is null, returns an empty array."
    "Returns: an array of selected columns or an empty array if nothing is selected or the selectionModel is null"

But by spec of setSelectionModel(ListSelectionModel newModel):
    "If newModel is null, an exception is thrown.".
Also default value of this method is not null too. So it's not possible to set selectionModel to null.

Probably all references to this condition (selectionModel is null) are obsolete and therefore should be deleted from the spec.
###@###.### 2005-1-17 16:33:48 GMT