Lets you control the different header options.
4.3.10.1.2. Delete Headers
To avoid header duplication, you have to specify at least one identify key
that can be used to uniquely recognize your header template. That way an
existing header can be removed before a new one is inserted.
A good key for the template mentioned above would be
Sun Public License Notice.
Most typically this will be your company's name.
You can specify several keys to make it easy to switch between headers. Specify
both a key for the old header that is to be removed and for your new header that
should be inserted. This way, you are sure that even new additions that happens
to contain the old header (maybe checked out from some SCM) are
treated correctly.