Write a program in java language that that reads in words from a file(input.txt is included in .rar ), while discarding numbers and special symbols (you should replace each discarded symbol with space).

The words must be stored in alphabetical order in a linked structure(s), with each node holding the word and a the number of occurrences in input file. (In order to decrease the running time of your program you may keep a separate linked list for each letter.)

The output of your project is a file named out.txt which contains a list of words with frequencies.\\

Remark

Avoid using global variables.

Convert every alphabetical letter to lower case.

Ignore all numeric as well as following characters:

@ # $ % ^ & * ( ) ~