You're right, the CommandLine constructor is package-private (default) access and therefore can't be extended outside the package. I don't think this was the intent of the developers, since the CommandLine and CommandLineParser classes are not marked final.
I attached a quick patch, if the comitters wish to implement. You'll need to realize the CommandLineParser interface in another class to return your custom CommandLine type, of course, and you should keep the constructor protected/private =).
On Tue, Sep 28, 2010 at 8:16 PM, Jason Powers <email@example.com>
I'm working with version 1.2 (I've checked the 1.3 source as well) and I'm
in need of writing a parser that's a little more strict than the provided
parsers. I really like the rest of the framework, but if I can't instantiate
a CommandLine object without being in the same package I can't extend it
Is there a reason that this is protected that I'm just not seeing?