likely if they are some things multi-dimensional arrays it'll probably be two at most maybe it'll just be single dimensional race and also with arraylist everything that we've done in this class which is also everything you need to worry about for the final is sort of the job la five-week-old later version of arraylist so in the book has always sort of two versions there's the jurors how to use our analysts before java five oh and here's how you use a waitlist after java five oh or five oh one later you don't need to worry about the before five of stuff just the five owned laters all you're going to need because that's all we've emphasized in the class in that's the these days what everyone views in any way paint and then after a raisin arraylist which was kind of the introduction to the whole notion of java collections was thinking about collections so besides just arraylist you also saw hash map which hopefully this point you were just been master of the hash maps but you should know the hash map and things that come along with hash maps and collections in general or the collection interface as you take elections for the collections is for example if the reader what is an iterator how do you get me iterator from a collection how to use in iterator right that's something that you just want to be fast so i would because chantelle for some problem to solve the problem specially for doing something that work for involved to hash maps you probably want to be able to get iterator and then you've got to know all hash map i need to get the set of keys right vicki said to be able to get the iterator on that so these are you know also good places to have tabs in your book them for quick reference if you need them and last but not least cp files rights or the basics of files and you've done a lot of the basics of files already know how tough open a file and read from a file know how to be able to write to a file needs right if i can tell you probably won't have the right to a file since he didn't have to do it on tv simon's but at least reading from the file is fair game so topically that's kind of what's going on given sort of the topics let me show you some examples of the kind of questions we might ask these scientists on the practice final which already have sort of a whole practice final that you can do and i would encourage you to do that under time condition so you can figure out what kinds of things you're maybe a little rusty on what kinds of things you're feeling good about here's an example the kind of question we might get right that involves a bunch these concepts which is given hash maps so given some passion apple typist hash map of strain constrained right and you know that these are teason values find essentially all ki values that are the same so what we want you to do is fine matching key value pairs what i mean by that but i mean it's not so we have some cash map were here the keys over here you are the values over here and i might have some keys like alice and bob and kathy and i might have some values like alice and kathy and so what i want to find out for example the print on the screen as i'd want to treat alice and i'd want to pre caffeine i want to matt white out any of the keys whose value is basically the same as their value in the hash so that's a very simple sort of set up but it stresses a bunch of these concepts that you need to know to be able to do it and that's kind of hopefully the way a lot of the questions are gonna be on the final is simple concept that stresses the ideas so if we want to think about solving that problem uh... right we might be given some header work public waleed matched he's and this has some plan where they discussed like attachment from strain destroying waqar map minus all the syntax should hopefully be stuff it's just a second nature to you at this point you really want to figure out how to solve the problem everything about this problem if we want to find out which cheese have similar values have the same value as their value what's the first thing we want to do running at a rate over the keys right we want to have some way of saying okay i need to go through all the keys and look at them to see if they have the same values the values i'd need to have some iterator iterator i know we have to be over strings kaczynski meter reader over the type of whatever the key is for the hash map alcoholic hit and how do i get an iterator from ashraf over the keys that attachment so i need to see map she said if you're kinda good things to know in the back your head iterator we sort of string these altogether and so what i know i'm dead iterator of strings which are all my cheese in the hash maps and now this point it's just using my generator but in conjunction with some other functions 