Is there any way to extend JFormattedTextField dealig with numbers
using NumberFormatter?

I would like to allow a null value input.
It seems that the most of the functions used in NumberFormatter (for
example NumberFormatter.replase) is package friendly
and inmlementation in DefaultFormatter.DefaultDocumetFilter use package
friendly calls to JTextComponent and doesn't allow subclassing and
overwriting them.

Where the poin of intervention? May be somebody already implemented
something like this?

Please help!
Vladimir