You are required to develop a Java program $($XRef$.$java$)$ that will generate such a cross$-$reference

map $($A Cross$-$Reference Map for a program is a list of all the identifiers employed in the program, along

with the line numbers on which they appear.$)$ for a Java source file. In the cross$-$reference map, the identifiers $($Identifiers are words used in programs to name variables, classes, methods, or labels and are

subjected to strict rules. None of the Java keywords$/$reserved words may be used as identifiers.

An identifier can begin with a letter, a dollar sign $($$$)$ or an underscore character $(\_).)$ should be listed in alphabetical

order, and the line numbers on which each identifier appears should be listed in ascending order.

You are NOT ALLOWED to use data structure classes provided by Java API. You must use

the linked list developed in this module for the assignment.

The following is a sample execution of the program with the given Sample.java as the test file:

C:$>$ java XRef Sample.java