With JExcel, you can hide/unhide columns like you would do in Excel.
(If you hide a column, it will not effect the datasource.)
To hide a column, simply click on the 
icon (1) the select the option 'hide' (2).
And to unhide all the hidden columns just click on the link in the right-upper corner (1).
To see which columns are hidden hover on the link (2).
If you want to display a new column (that was not displayed before), see the Display/hide columns section.