JSAP parses your command line and
instantiates objects of types you specify based upon that command line.
If you configure JSAP to expect an
Integer on the command line, and the user does
not provide a String that can be converted to an
Integer, JSAP will alert
your program to the fact that there was a problem with the command line.
If JSAP indicates that your command line was
successfully parsed, you are guaranteed an Integer
when you request that parameter's value from your program.
There's a pretty big (and growing) list of return types suppored by
JSAP; you may want to skip
right to the javadocs and check it out.
JSAP provides not only for default values
for its parameters, but for a cascading chain of values. With a couple
extra lines of code, JSAP will, for example:
Parse the command line.
For any omitted parameters, look for values in ~/.yourProgramName.conf
For any still omitted parameters, look for values in /etc/yourProgramName.conf
For any still omitted parameters, use the default values (if any) specified by the developer.