java - Dividing a string into all possible 4-letter consequent phrases -

what i'm trying this:

1. read file;
2. remove punctuation , convert letters lowercase;
3. convert words 4 letter phrases (if word shorter 4 characters, take whole);

example:

input: hello, identification mister dude.

output: hell, ello, my, iden, dent, enti, ntif, tifi, ific, fica, icat, cati, atio, tion, is, mist, iste, ster, dude.

it nice if each 4-word phrase separate value in array.

now things i've managed complete:

public string[] openfile() throws ioexception {     filereader fr = new filereader(path);     bufferedreader textreader = new bufferedreader(fr);     int numberoflines = readlines();     string[] textdata = new string[numberoflines];     int i;      (i = 0; < numberoflines; i++) {         textdata[i] = textreader.readline();         textdata[i] = textdata[i].replaceall("[^a-za-ząčęėįšųūž]+", " ").tolowercase();     }     textreader.close();      return textdata; } 

the textdata[i] each line of text need divide. i've tried several methods, such .tochararray , 2d arrays can't seem manage letter arrangement part. how can complete task no.3?

tested on ideone.com:

public static void main (string[] args) {     string text = "hello, identification mister dude.";     string[] words = text.replaceall("[^(\\w )]+", "").tolowercase().split(" ");     (string word : words) {         if (word.length() <= 4) {             system.out.println(word);         }          else {             (int = 0; <= word.length() - 4; i++) {                 system.out.println(word.substring(i, + 4));             }         }     } }