Need help filling in the code with JAVA, I've highlighted what needs completing.

import java.io.File; import java.io.FileNotFoundException; import java.util.Scanner; import java.util.Set; import java.util.TreeSet; /** * UniqueWords - Write a program that uses a TreeSet to print each * unique word from a file alphabetically * Based upon P16.1 in Big Java */

public class UniqueWords { public static void main(String[] args) throws FileNotFoundException { Set  words = readWords("wordlist.txt"); for(String word : words) System.out.println(word); } /** Reads all words from a file and puts them into a set (a tree set) @param filename the name of the file @return a set with all lowercased words in the file. Here, a word is a sequence of upper- and lowercase letters. */  //-----------Start below here. To do: approximate lines of code = 6 // 1. static method readWords returning a set of Strings ... FileNotFoundException {//opening of the method //2. let 'words' be a set of Strings, constructed as a TreeSet //3. let 'scanner' be based on a file with name 'filename' //4. let scanner useDelimiter any run of one or more (+) characters //other than a-z or A-Z //5. while scanner has another word //6. Put the lower case version of that word into 'words'. return words; //returning the set of words from file 'filename' }//closing of the method //-----------------End here. Please do not remove this comment. Reminder: no changes outside the todo regions. }