Query related to Apache Commons CLI

[Sruteesh Kumar]

I have a doubt on Apache Commons CLI

For DefaultParser, why is a negative number preferably considered as an 
argument rather than an option

Consider the following case, for example:
String[] args= {"--one","arg1","-2","arg2"};

Here, -2 is considered as an argument to --one, even if there is a required 
option with key -2

Why is it preferably considered as an argument rather than an option?