Java Collection Framework – Part 2 | Advanced Concepts & Examples

Key Takeaways

Hello guys. Uh so today's we this is the second lecture related to the Java collection topic. Uh we are going to discuss uh the few lectures uh we have associated with the Javas and we already have understand uh few knowledge about Java uh topic as well. So uh since we have an idea uh how we have covered uh so far little to the topics let's uh understand which is the second lecture to the Java collection that we are going to uh cover here. So the topic we are going to cover is what is arrow list. Then uh we will be checking out some declaration of arrays list. How we can do that? uh we already have uh understand some of methods which uh came from collection class. So since uh error list is implemented class for the collection class uh collection interface. So the the we methods we have uh discussed are like add methods uh remove methods, contains methods, size methods. So these are the methods which we already have an idea about it. Uh so we will going to use those methods and uh similarly there are new uh add-ons method which was uh provided by the array list you can say new methods or you can say overrided methods in array list such that uh addition with two different parameters such as indexing in the object one. Similarly, we are going to check the remove indexing. Similarly, uh we going to check uh one more method which is index method. Then we are going to use the set method for indexing and then uh object what we are trying to make an updation into that. We are going to understand using an example uh regarding the same. Then uh in the array list we are going to check the retrieval data from array list. How we can do that? Whether we are going to cover three different uh loop inside that uh which is for loop uh for each loop and uh there is one more topic which is known as iterator uh through which we are going to iterate the values as well. So that we are going to discuss uh as well on the topic. So after all this discussion we are going to start with a similar kind of a thing in one more topic which is uh instead of array list we are going to cover the set. Then uh we are going to use a headset. uh how we can declare the same uh predefined methods and uh since after this uh we are going to check the retrieval data from uh set or you can say h set uh we will use uh different uh looping whether it's a for each loop or the editor loop to use the same then we are going to check about the automation perspective how these things uh is been dealing with those so these are the topic for the agenda which we are going to cover in current lecture. So let's uh start with our today's journey uh with which is related to the array list. So we already have prepared one document which uh we are going to cover uh for today's lecture which is uh the Java collection automation part two. So the first thing is what is arialist? Since we have an idea yesterday that arist is a class which is uh came from uh collection interface. So it's a it's a package inside a util one. So uh since we have understanded the collection topic collection can be a dynamic value. So same ideology will be associated with the array list. Uh we don't need to define the size it it is dynamic. Uh resizable arrays kindly you can say. So uh insertion order is being maintained because it's a part of a list and uh since it's a part of a list duplicacy is also allowed with the same. So uh as we have heard about it uh array is of homogeneous and array list for the heterogeneous. So it we can add any number of values into inside that uh that specific uh value of the array list. So we can uh this is a brief idea what is an array list all about. So now we will move to the declaration of array list. How we can declare array in our programming perspective. So let's uh create one class or you can say one package. So let me uh reinstall re initiate the intelligent first. Yeah. So it's loaded. So let's say uh intentionally uh let's create one uh Java class with the name of array list example. So this is the class I have uh created inside that and uh let's create a main method. So it through which we can run any program. So for the declaration part like uh we did in this uh for any class declaration how we can do that the class name then object is equal to new and then class constructor. This is how we are going to call the uh create a reference variable with the same ideology is being associated with since array list is a class. So uh we can create with two different generic methods. So array list is a class. So this is how we can create a array list. Let's say I have created a name of the variable is list using new array list. This is how we can create a array list type. Since uh this is known known as non generic way of creation of a array list but there are few more as well. Uh let's say generic one. So let's say uh instead of uh declaring the any type of value it's uh array list can hold only a string value that that is what uh you supposed to do that. So how we can achieve the same you just need to define the type. This is how uh known as generic way in which this array list can only hold the string value. Before that it can hold any value. And what does add value here represent means adding for example let's say 50 is being added. Similarly list one dot add let's say a j is being added. See uh this is integer and this is array. So it is acceptable because it's a uh non- generic way but let make it as generic. So let's say I have added as a string. You can see it is being pointed out as a a error in the compile time error. So for this it is uh suggesting some suggestion that you can convert that integers into a string as well. So this is a through which known as generic way. Similarly there is one more way instead of declaring array list here we need to define the implemented interface. Since it's a part of a list we can use list way as well. So this is how we can create array list. This is known as using list interace way. This is the three different approaches uh which we can declare an array. So that's we have uh understand about it. So uh these are the three different ways which we have covered. Similarly these are the topic the definition I have just uh teach you about it. So uh since we already have covered some methods yesterday about the collection interface what are those me methods such as add for adding some values for removing we are use going remove for verification if that object is being present on that collection or not we are going to use contains uh for clear uh clear out all the values for size we need to check the size how much the collection sizes uh size will be used is empty is used to verify if the collection contains any data or not. So these are the predefined method which is present in the collection class or collection interface. Since array list is a part of the collection interface automatically these methods will inherit to that array list. So apart from these we can have multiples method which is can be overloaded in the array list and what are those methods? So these are the four different methods that is being used as a overloaded thing. So let's understand uh with a few example for uh more knowledge about how the codings look like of all the uh associated methods we have in the analyst. So uh let me uh we already have one class uh for this one. Let's say I have declared a array list of let's say uh we are creating a generic array list which accept a string value. So let's uh make it as fruit. So this is how we have declared a array list which can hold any uh string value. So let's say uh since these are the predefined method which is of collection interface. So we can add the value here as well. So let's uh use those functions by calling the reference variables. You can see uh I have added orange. Let's say I have added uh apple. Let's say uh I have added banana. So these are the three different uh you can say uh uh approach we have added. So add object. So this method came from collection interface right. So we are going to use directly here. Similarly, let's move on to some new method which came from the array list which is add index object. So what does it indexing means? So you already have an idea like in array. This is a zero index. This is first index. This is second index. Right? So let's say I want you to add at the index number one. How we can do that? So uh insertion is being associated with it. So fruits dot at one dot let's say I have added grapes. So intentionally what is happening here insertion at index number one. You can see now it's zero as orange grapes at one second as apple third is banana. So this is the new updated string you can see. So let's uh print the value to show you that value. So after index insertion so let's say I have uh intentionally print the value. So what does it uh print? So let's uh first it will print orange then grapes then apple and then banana. So these are the output uh it's going to show you in the output perspective when we run the program. So you can see first is orange then grapes and then apple and then banana. This is known as uh adding at a specific indexing can be occurred. Similarly same remove indexing was being associated that means uh if we wants to remove at that index so it gets slightly changed to the previous positions. For example, intentionally I have added I have removed apple from this. So how does it uh strings look like? Orange, grape and then banana. So this is how the programs look like. So let's uh remove the same and uh check the value. So fruit dot remove let's say intentionally I have removed apple. So this is what uh the values look like. So uh after removing apple so what does it fruit uh will display so let's uh show you the output here you can see I have removed apple so it gets removed from there and the final result will be orange grapes and banana this is how the remove at indexing will look like then similarly there is one more function getting index that means if we provide the index number it will provide that associated value. Since we have an idea is set zero at in orange first is grape and then banana is number two. So after this let's say I use get function to provide a input as a one that means it will print output as grapes. So let's say this is what uh I want to do. So let's say string second index fruit this is what I wants to gr fruits dot get second this is what I wants to print so let's say this we already have stored into the uh some string so we can directly print that string Second indexing fruit. So what does it print? It will print banana because at the end you can see zero is orange, first is grape, banana is second one. So at the end it is printing the banana in the output. So after this we have understood a few functions which is provided by the new uh array list which is add uh provided the index and the element that we wants to add removing with the project of that object you wants to remove uh the get function to provide the what value it is holding in the array list. Similarly, there is one more function which is known as set that uh like we did in the add. It is inserting but that will make a change into that. For example, like this instead of uh now we have added the grapes at the first index. Right? Instead of now at the same first index instead of making a grapes we are changing it to the kohi flower. This is what I have done. Okay. So after changing insertion what does it print? So it will print orange then cauliflower then apple and then banana. So this is the output we can see in the by replacing a set function we can see orange grapes apple banana after indexing after making a changes using a set function the grapes will be changed to the cauliflower. So these are the functions which has been provided here by the uh overloaded method by the array list. So any doubt guys if you have uh just let me know in the chat section uh we can uh sort it out here. So these are the predefined u method which has been provided by the uh topic name. So let's understand how we can uh retrieve a data using a list. So uh let's move on to the three different ways we can uh retrieve a data in an array list. First is using for loop. Second is for each loop and then iterator. Those these are the three different way we can uh retrieve a data from a an array list. So let's understand one by one to uh get the data. So intentionally uh I have added some data uh which is this orange, apple and banana. These are the uh fruits I have added in the array list. So I wanted to retrieve all those datas. Uh how we can do that? Let's understand with the four each four loop example first and then we will move one by one. Okay. I =0 I less than fruit dot size I ++. So this is how we are iterating each. So I wants to get this first this second and then third. These are the indexing right. So zero index first index and the sec second index. So if I use I function to use a get function automatically we going to use the same. So how we can do that? Fruit dot get index. If I use this function first it will go with the zero value. That means fruit dot get zero it will print orange. Fruits dot get one it will print apple. Then fruit dot get two it will print banana. So these are the approach we can use. So I'm just uh using this here. You can see this is how we are printing all those value inside the array list using a for loop. You can see orange, apple, banana each value has been retrieved here. So similarly let's move on to the one more approach. So let's uh comment it out. Another approach is using a for each loop. Right? What does it for each loop represent? Since uh it's a p of a string. So we need to def uh define a item and uh where we are going to use item is we going to print the same. This is how we can use a for each loop. We already have understand about the for each loop when we have uh taken out the topic for the uh associated Java uh topic in the looping concept. We can see same ideology be there. So now there is one more approach which is a new approach that is provided by the collection as well. That approach is known as iterator approach. And how we can do that using an iterator. So let's understand uh with the example. So in iterator there is predefined functions. What are those functions? First is iterator. Iterator function is used to tell which data are we iterating. For example, I'm iterating the fruits. So I will be calling this iterator function using fruit fruits. So fruits dot get fruits dot iterator will go line by line means go line by line for which iterating which things that we are going to use. Second thing is iterator is a class. Since it's a class, it has some functions. What are those function? First is iterator functions. Second function is a has nest function. Then function is next function. And what does all those function represent? Since you already have an idea about the iterator, it is used to just uh check which we are going to iterate. and has next will verify if the element was present here or not. So let's say first it will check the orange. So data is present. So it will note null. Similarly then after reaching the banana we are trying to move the h next that means this array list has been reached till the end point and there is no such value has been present. So h has next will return the null value. So this will be used in the for looping thing. Next value is used to get the value like we did in this get function. Same get function is being used like here for fetching the value at the indexing part. So let's understand uh with the example here. So let's say iterator is an uh class right. So it will hold a string value. So itr is equal to fruits dot iterator. So by this we are iterating each element. Okay. Now after this so while loop it dot has why it is iterable iterator it do has next until it is it is uh you can say value is present Right? The loop will being used. Then what we are going to use like we did in this fruit get same function is being represent here in the next function. So it dot next. So this function this approach will print the value similar like this orange apple and banana. So let's execute the same. So check you can see it is still printing the same value. This is how the retrie of a data in a array list look like. And uh now take some example in the realtime perspective for more knowledge since in this pom.xml uh I have already added uh some uh junit uh some APIs uh sessions as well. So you can see I have added some dependencies related to the uh selenium. So we can uh call those selenium classes as well. So let's uh understand the selenium uses in the real time perspective. So let's say there is a web driver is equal to driver new chromedriver right similarly web driver manager dot chromedriver dot setup using these line uh the web driver gets opened right then this driver dot manage dot windows dot maximize will be maximizing the same similar Similarly, driver dot manage dot timeout dot implicit weight will add some weights for each of the web elements. These are the pre uh requisitive that every function needs to be done. So, uh don't bother much about it. So, now driver dot get. So, let's say this instagram.com this is the website, right? So these are the website uh that we have right uh let's say I wanted to check all those web elements that it can contain that means how many a tag is present on this web page all the links that I wanted to fetch. How we can do that? Since every link is being associated with a tag which is of uh a tag. Okay. So how we can do that? You can see uh link tag is being used in every referencing. So link see there are lot of links is been present on the website right. So I want to fetch all those uh links. How we can do that? We can use the link uh method to fetch all those tags that have been associated with it. to let's open this Instagram.com driver dot find elements by dot tag name. You can see the tag name is link right. So we can just copy paste it here. This find elements you can see it is returning the list of web elements. List of web element there are complete list that we can store. So list of which web element let's say all all links. So this is how we can fetch all the specific link and let's say I wanted to print those links. So web elements right let's say link dot all links and s out link dot get text. So this is how we are printing all those links that is present on the web page. So you can let's uh print the value and uh check if the output is being working fine or not. You can see the chrome browser gets open. Instagram page is being loaded up and uh everything looks good right now. It is not able to fetch the value. So let's use a anchor tag to check if the all those link has been associated with the anchor tags or not. You can see wherever the anchor tag was present every link is being populated here. This is how we can get all those links that have been associated with the anchor tag. This is a realtime uses in the automation perspective when we are dealing with the uh collection topic. We are storing all those web elements and for using for each loop we are printing those value like we did in the printing of array list. So let's uh understand few more topic which is the second one which is uh set. So the now the second question arises similarly what is set? How we can declare a set or you can have set? Uh since we already have an idea about the collection uh classes then retrieval retrieval data retrieval data from a headset. So that we already have an idea about it. So uh let's understand this topic. So uh let's open the document for more knowledge about it. See uh what does it uh say? So what is set first question is it? So hi sir will I able to understand as I haven't seen any previous video yet. So uh Rakkesh you needs to uh go through the videos previously on mine uh that will be help you uh to understand more about this Java collection. There is only uh one video for the Java collection but uh we have covered nearly 10 videos for the Java topic which is necessary for being an automation tester that you should have an idea. So just uh go through those if you want. So let's move on. So what is set? So that is an interface. This inside interface uh there will be some implemented classes that we have. So the implemented classes generally we we people use are headset. So headset is the implemented class that we are going to use. Then uh like we did in the mathematics uh in set there is no such duplication is being uh added that means if I wants to add the same fruit like we did here. Let's uh remove all the previous codes like this uh where we have added orange here. Similarly, if I add orange again here. So, this is possible in array list but not in the set because set doesn't support the duplicacy. It will only add once here. If I print directly fruits, if I choose instead of array list as I said that it will uh in the list there is only two data. First is orange and second is banana. So this is the main difference and second is unordered. Unordered means uh this is the first index, this is a second index and this is a sec zero first and second index. So the order is not in preserved it will add at random order. Banana can be came first as well. Orange can be came second as well. any uh things can be happened in the set. So this is the second difference between set and the array list. So now the topic here is what is headset? So headset is the implemented class of that set. It's a very important. So same preservative that we have in the set. Same goes around with the set and the headset as well. Doesn't maintain insertion order allows no null value past access and uh since it's a duplicacy is not allowed. So how we can declare a headset in our uh I want some boyfriends. So the how we can declare a headset. So the declaration can be very easy. Uh there is only like we did in the uh array list same ideology is being associated with it. Instead of this we can declare like this. This can be also used as well. This is one approach. Right? Second approach is generic. This is the generic one. A non-generic. It can be accept any value. If I make it as specific type, it will only accept the uh specific type. Similarly, uh like we did instead of set uh we can have headset as well like this. Similarly, asset can be removed. Anything uh all these things can be accumulated as well. So, uh these are the four uh declaration through which we can create a headset or a set associated with it. Since uh it's a part of a collection as well and under the set category, every function which is part of the collection interface uh will comes as well in this as well like add function, remove function, contains, clear, size, all those methods. try to use those uh on your own and uh write those uh class which you have been associated in the chat section of this uh video lecture and then we can good to go. Then after this let's say how we can retrieve the data using a hset same uh if you want to run uh the punchu how we can learn the java for being an automation tester if you want uh I already have uploaded some of the basic ideas how you are proceed you can proceed with the java go to the previous lectures in the gigs for gigs channel in the live section you will see nearly 10 to 11 videos associated with the java which I have taught you you just go with that and uh you will able to understand the basic terminologies how the Java in the automation looks like. So let's uh understand with the programming knowledge about it and uh use the same ideology that we have in the programming itself only like that let's say set and it is accepting a string correct this is how we have added uh created a set similarly we have added multiple uh data you can see orange orange I have added two multiple times and uh since it is not accepting any insertion order we can just uh remove those. So I wanted to show you one thing. So that's why intentionally I have added two duplicate duplicate data. So let's say selenium let's say API. So I have added nearly five datas right? Uh this is the first index the zero index first second third and fourth. If let's say if it is you don't know uh if a set is unordered or ordered. So that means how we can check that we can just print the value and we we will get the output. So let's say I want to print the fruit. You can see it is first uh adding API selenium and orange and banana. There is random order it is entering. Similarly I have added ordered added orange two times but in the list it is appearing only once. So it is removing the duplicacy also unordered insertion order is being maintained in this. So these are the few points that I wanted to show you here. Now how we can retrieve a data same ideology let's say for each loop for loop for loop as well we can use uh we already have an idea. So let's say I have stored all those into a string. So I have used string as well. So how we can do that system out.print l. So just print the value it will provide all those necessary details. You can see API selenium is banana. So these are the you can see uh I have print using for each loop. So let's uh understand one more which is a iterator approach. We already have seen same ideology use can be here as well. So how we can do that? First we need to create a iterator object of a string type. Let's say reference variable named as iterator and instead of new it should be fruits dotiterator. So now this iterator is being used for has next function and similarly next function as well. So while loop right iterator dot has next s out dot iterator dot next. That's all. uh let's instead of let's make it as commented out only one time it get printed. You can see this is printing the same data. So by two different approaches by using for each loop and similarly by using iterator loop we have printed the value uh inside the uh set value. Uh the punchu is saying Java or coding Java coding both are the same thing bro. Uh means to understand Java for being if you wants to become an automation tester you first needs to understand Java how you are able to write the code in the Java where those Java code is being used in the automation usage. So then only if you are perfect in Java then only you will able to understand the selenium or the rest assured the APM because both are all of the have as a tool that means they have the classes and the function that you are going to reuse it again. So once you have a command in the Java everything will be aligned automatically. So that's why I have chosen the real time example of Java's topic which is necessary for being an automation that you should have an idea so that we have an uh understand about it. These are the retrieving of data. Now we will move to the some uh headset realtime example in the perspective in the automation. So let's uh make it as web driver dot manage.com chromedriver set it up webd [Music] driver python or java who is best uh I was suggesting that you should go with the java why uh because there is more opportunity more persons more community support since more community support is provided uh more challenges you can uh tackle up python is have predefined function. So you don't uh know much the conceptual knowledge about it. So I was suggesting you ban to move with the Java first. Uh so you will align everything about it. I hope you are able to understand the point. So uh let's say uh using driver dot manage dot timeout do implicit weight duration of second. Let's say I have added 5 second driver dot manage windows.imize maximize. So, uh I have added uh multiple things. You can see let's say this is the instagram.com right after this uh let's say I have intentionally click on this sign up button, it will navigate to the new page. Similarly, if I click on this login button, it will navigate to this page. Right? Let's say this is the uh automation practice. After clicking on this open new window, you will see new window gets opened. Similarly, after clicking on this new tab, the new tabs gets opened. So, all these things are a new windows, right? So, uh these windows can be handled using headset. So, headset is used because every window is part of a set of a string. So we need to store the set of a string and we can iterate using uh for loop for each loop and iterator everything can be associated with it. So this is the website that we have and these are the different element which which we are going to click. Let's say uh this is what you are supposed to do that. So driver.get this is the website that we are trying to help. After this uh these are the web elements. So let's find those web element. Uh the web element techniques is uh different things. So I'm just directly using what? Uh so it's a type of a id. So driver dot find element by dot id and just providing the same and then click. Similarly driver dot find element by dot. So this is the one more element which is a open tab which is of open tab. You can see by dot id this and this is what I'm just uh clicking those web element nothing more than that and in this website is being loaded up you can see let's understand with the one proper approach that is what is happening first it is opening this web browser then it is navigating to this URL like this after this uh it will click this open window element like this And also it will click this open tab as well. So this is what is happening here right. So how we can get all windows handles that is being associated with it. So there is a function which is known as driver dot get window handles. You can see this get window handles is returning set of a string. That means we need to store those into set of a string as well. So set of a string let's say window set and using this window set we can iterate. How we can iterate? We can iterate using for each loop. Let's see for loop uh string is a type of window window head set that is what we are trying to iterate driver dot switch to dot window handle right s dot driver dot get ID Okay, this is what uh instead of this let's only uh click the single tab. So there are two different tab is being opened right. First it will click on this window. So there are two windows. First is this set. Second is this set. So there are two data inside that set. So let's uh print this uh if you want you can print this window set as well. So just printing out printing out window and set data nothing more than that. So this is the output that we're trying to do. Okay. So let's print the value to check if uh this set iteration is being working fine or not. You can see website is being loaded up. It will clicking on the open window button. Then second window is being loaded up and then you can see everything was allowed here. You can see in the window set there is two different browser is being opened. First is this, second is this. So that's why there are two datas inside that set. This is first data of browser. Second is the second browser. Similarly uh in that we are printing the title nothing more than that. You can see this is the titles and this is the second title. If you want you can just click here. You can see practice page is the title. Second title is this QA click academy testing all those different values. So that's why it is printing those two different that's all uh for today's lecture guys and uh I hope you are able to understand uh the set and uh a list. So uh we have understanded in the automation perspective as well uh while switching between multiple browsers window handle how we can collect all those window handles and uh since uh set is not allowing a multiple uh in same data so that it can hold only a single data as well. So that's all for today's lecture. We'll meet you tomorrow. If you have any doubt you can just note uh down into the chat section if you want. Thank you everyone.