This is Perl module App::checkstyle.
INSTALLATION
App::checkstyle installation is straightforward. If your CPAN shell is set up,
you should just be able to do
% cpan App::checkstyle
Download it, unpack it, then build it as per the usual:
% perl Makefile.PL
% make && make test
Then install it:
% make install
DOCUMENTATION
App::checkstyle documentation is available as in POD. So you can do:
% perldoc App::checkstyle
to read the documentation online with your favorite pager.
Dann