I M confuse on this Java code

Researchers have found that when a book written in the English language is analyzed for letter frequencies, the expected order of the eleven most frequent letters beginning with the most frequent is: E-T-O-I-N-S-H-R-D- L-U. Your assignment is to find and print the frequency of all of the letters of the alphabet appearing in the text from Sonnet #18 (see below). Ties will be decided in favor of the lower letter in the alphabet. The input will be Shakespeare's Sonnet #18 found below. You will need to store this in a data file, first removing all of the capitalization and punctuation, so you are only working with lower case letters. The output consists of a string containing all of the letters in the text in order from most frequent to less frequent. Ties will be listed alphabetically. Also, include the number of occurrences of each letter. This program is to be well written and documented both internally and externally. Sonnet #18 Shall I compare thee to a summer's day? Thou art more lovely and more temperate: Rough winds do shake the darling buds of May, And summer's lease hath all too short a date: Sometime too hot the eye of heaven shines, And often is his gold complexion dimm'd; And every fair from fair sometime declines, By chance or nature's changing course untrimm'd; But thy eternal summer shall not fade Nor lose possession of that fair thou owest; Nor shall Death brag thou wander'st in his shade, When in eternal lines to time thou growest: So long as men can breathe or eyes can see, So long lives this and this gives life to thee