Java Collection introduction for Automation

Key Takeaways

Hello guys. Uh let me know once you uh my voice is audible to you then we get uh started with today's lecture related to the Java collection. Hello guys. Okay. So the my my voice is audible to everyone. Uh so let's get started with our topic. So this uh Java collection is all about uh three different lectures. So I have divided into three separate parts that we are going to discuss it today. So the first uh topic uh in this we are going to discuss is uh about what is Java collection and what is the difference between array and the collection why we are move from array to the collection in the real time perspective. After this uh we will be have uh understand about the collection interface versus a collection class and then we are going to use with the some of the example in Java code level which then uh we are going to discuss about the collection hierarchy diagram uh what does it represent and uh we are going to discuss some of those uh classes and interfaces related to this. Then uh we will be understanding about the list basic identity and then we are going to discuss about the set and then we are discussing about the map interface hierarchy. U we not going much about all those uh that we are covering those uh later on classes because it's we have divided topics into three different sections. Then we are going to discuss about some uh some common collection method that is being used in the realtime uh uses. So I have prepared the same then I will summarize for the today's lecture. This is the all about that we are going to discuss with today's topic uh with related to the Java collection. So I hope you are able to uh understand today's agenda. So let's get started with our today's topic. So the first topic is what is Java collection? Let me just uh copy paste this and uh into the notepad section and then we can start it. So u what does Java collection represent? So Java collection is kind of a framework that provides an architecture to store or manipulate a group of objects. Let's say uh you have you wanted to store list of web elements. You wanted to store uh web elements of n times. So uh instead of creating n web element n number of times there is an approach which we can use. We can create a list of web element and we can store all those web element into that and we can manipulate uh whether we want inserted we want to delete it every action can be performed with this same ideology. Similarly uh we want to store the JSON uh data in some let's say you wanted to store some JSON data. So instead of creating uh a JSON object all those values we can uh create a map and assign it to API for uh data. So this is how we can use uh Java collection as well in the realtime perspective. This these are the common uh web automation perspective that you can use. Similarly, you want to uh make a for example, you want to store some Kafka topics as well, then you can also use uh Java collections of array list to store the response that we get in the Kafka topic. All those things can be associated with the Java. when you understand the Java collection, you will able to uh store all store those objects and um manipulate whatever you wants to do. So uh since we have an idea in array or in any sort of things. So searching, sorting all those things take we needs to write some codes uh to do that. So these are the functions which is already provided by the Java collection. So we are going to directly directly call those function and provide the value. For example, in uh Java or in array, you wants to add some value. So then we can use uh the uh in in incremented value of the array and then we are uh add those value. Similarly, if you want to delete some datas into that you you need to remove the space from that array and uh traverse back all those values. This is how you are deleting the object. Similarly, if you want to search some data, you you need to navigate one by one each every data. So this is how in the array looks like. Similarly, if you want to store some new data, we need to increase the space of array. Then only we are able to store the. So these are the challenges that you are facing when you are dealing with the primitive uh types of data in the Java. So those uh challenges has been fulfilled by the Java collection. We can store values, we can search values, we can sort values, we can insert, delete everything with the help of functions which is provided by the Java collection that we are going to use. So real time uses as we have uh seen you here with the three examples where we can uh store the datas in the input form of uh JSON objects like in the map uh like in API responses as well. Similarly, if you want to uh store the test cases list, we can also use a list of uh arrays and whatever we want. Similarly, if you want to store the web elements, we can use list of web elements. So, these things uh can be used in the Java collection in the real-time perspective and we are dealing with the automation knowledge about it. So, uh the question arise between uh what does the array and the collection uh there's a difference on that. See uh we have discussed about the array topic uh before. So in the array we have ideas that uh array is of size fixed. Uh and uh since array is a fixed type uh we have an idea as the data types on those we can be primitive or objective performance uh a slightly fixed only for the fixation data. If there are some manipulation needs to be done then uh it takes some a lot of time right. There are very less utility methods which is provided in there. We need to create our own and then we to utilize those. So all those features or all those features has been associated with the collection. In the collection we the size is not fixed. So we it's a dynamic we can add delete any sort of things. Data types it can hold the objects only. Uh if you wants to store the integers, if you want to store some uh web elements all those things can be stored in the data types. Similarly if you wants to perform uh for the performance wise since it's a unknown size flexibility can be associated with it. Similarly, utility methods uh since area doesn't have limited utility method but collection have a lot of uh methods which is provided for adding, deleting, searching, sorting all those values. We are going to discuss all those uh methods later on in our lectures as well. So let me understand uh this is the example uh that I'm going to show you with the programming logic for more understanding. Uh let me open the intelligent and uh in the intelligent we are going to run the program here itself only to understand the difference between array and the collection. Let me boost white performance. This is the error right? Uh let's create one more package with the lecture instead of lecture let's uh create one more package inside of the Java with the name of collection understanding. So inside that let's create one class for uh knowledge about a array versus collection. So I have created one class. Okay. Inside that let's create a main method. So um where we we can run the class. As we have an idea uh we can create an array of any type whether it's a primitive whether it's a non- primitive. Let's create an array of non-primitive type of a string. So using array let's say I have created one array uh with the name of name of reference variable it and it can store of a size three okay so let's say array zero what does it represent we can pro provide any value similarly we want to store 1 2 1 and two these are the different values we can uh store. Let's say this is selenium, this is Java and this is API testing. So I have created uh string of array which can hold three different associated value. So uh if I wanted to print the value how we can do that? So we already have an idea uh using array element right we have needs to define the size then only it can be proceed so let's say for loop string tool reference variable I have created so it's a string type. So we can just uh print that string two. So what if I print this? So it will print selenium API testing in Java testing that uh we already have an idea about the array. Since if it wants to add the value at index number four, it is not possible. Right? Let's say intentionally I have added this okay dynamic testing dynamic testing I represent I'm just adding a text you can see array index bound of a text exception we needs to define the size first then only the things needs to be added so this approach will be uh counterfeited by the you can say Java a collection. So let's say I have created one collection and that collection uh let's say of list type list of string collection and it can hold the array list since we don't need to define the size. This is how we are creating a data. Okay. And uh we don't need to do that. Uh there is a function which is provided by the uh collection class is uh let's say add using add function we needs to we can add the value whatever we want. Okay let's say this is the variable using this we can call the value uh let's say same ideology I wants to add this is the first element that I wants to add here. Similarly, we can add a few more. 1 2 3. This is Java. This is API testing. And here intentionally I have added a dynamic values. simply means we are adding more than uh we have defined because we haven't defined any value right so uh these are the collection elements so if you wants to print the same instead of array it should be a collection and we can just printing the value on this so what does it print see the array element is this and collection element is this so we don't need to define the size and automatically whenever I call a add function it gets added here. So this is the advantage when we have seen with the array and the array list. So we have seen one example how the difference between array and the list. And the next question arises there is a topic which interview probably ask you uh during an interview as well. Uh what is the difference between collection interface and the collections class? So the collection is an interface and collection is a class. This is the first uh difference. Okay. Since it's an interface, we cannot create a reference variable. We needs to have a class associated with it. And those classes are array list. And we are going to cover the hierarchy later on. Uh let's talk about the array list so far. Now we are taking an example of array list here only. Similarly, collection is a class. So that means the functions can be provided with this class and these function can be used. So collection is kind of a utility class like we seen in the uh automation perspective. We will creating some utility class for example config reader we have created yesterday and then uh we also created one excel file reading. So all those are utility class which provides some function that can be used to perform some actions. So same ideology is being associated with it. So collection is a class that will perform some actions. What are those actions? The actions such as sorting, reversing all those actions is provided by this class. So automatically if he wants to call uh the sorting mechanism on and these and and what where it going to apply it will apply on the collection class whatever he wants to do. So let's uh take an example here for more understanding. Uh so you will able to uh generate the same for more knowledge. So let's say uh one more class let's say collection versus collections. So collection we already have seen collection is a class and collection is a sorry collection is a uh interface and second one is a class. Okay so let's say intentionally I have created one array list. a collection interface analyst. See uh analyst is a class right? So this is the implemented class of that interface. So using this we can call the functions. So we already have seen one example here. I have created one array list and this is the function which we can use to add some values. Same thing I going to use here. So we can create a list. Let's say I have created a one string type of a list which can store some names. Okay, this is how I am. Right now you have seen I haven't declared any size of as well. So we can add any number of value. Let's say names dot add let's say AJ. So instead of this let's make it all those inside the main function then only we are able to do so. See we have added a name AJ. Similarly let's say I have added one more name let's say Rahul. Similarly let's say I have added one more name uh Zara. Similarly let's say I have added one more name which is Ankit. These are the names I have added. Okay. So let's say uh before that let's print this original list. Okay. What I once I print the same you can see it will print AJ Rahul Zara and rank whatever the value we have associated with. Let's say I wanted to perform a sorting ideology. If I wanted to perform some reversing, if I wanted to shuffle these, all those things is being pre-provided by the collections class. So collection as a functions which we are going to use the same. So let's uh understand more about it. So collections is a class that has some functions and what are those functions can be used like uh sorting we can perform reversing can be performed uh random shuffling can be performed these type of function can be performed with the collection class. So how we can do that? We just need to provide the collection which type of action you are going to proit. See collection is a class. So we need to call those functions whether it's a sorting, reversing and random stuff. These are the static method. We can directly call using a colle using a class name. See collection is a class and using you can sort things you can uh reverse thing you can shuffle things. So let's say intentionally I what I want to store I want to store this list. Okay I have stored the list then we can just print the value. sorted list also let's say I have been doing second action what is the second action reversing so instead of this let's say reverse I'm going to perform reversing list similarly let's say I wanted to shuffle this so the function is shuffleeness so all those actions is going to do and since the sorting is based on the sky so the larger value will come uh later on and the smaller value come on the first one so these are the output let's say to show you the output you can see this is the original list we have right AJ Rahul Zara and Ankit and what is the sorted list first AJ then Ankit then Rahul and Zara sorted list will be shown similarly reversing the order that means Zara Rahul Ankit and Aj Okay, so we have sorted this one. Similarly, shuffling again. So this list has been shuffled to Ankit, Rahul, AJ, a JNR, any random values. So this is how the collections class is being used in automation perspective. If you want to sort some list of web elements that we can use this using a sort function directly. If I want to reverse those values, we can use the reverse functions. So this is the utility that we are going to use. So it's a utility class that is being means to provide on which actions we wants to perform. I hope you are able to understand so far. Uh let me know in the chat section as well if you have any uh doubt about this topic. So let's uh understand the next ideology which is a collection hierarchy diagram. So the collection hierarchy diagram is simply is a representation of the classes and interface. How does it uh extending like you have seen uh in Java we have a support of inheritance which is being used from uh parent can adapt uh parent can have a have some functions those functions can be provided to the child as well. So these thing is known as hierarchy right. So the in red dot uh represent means interfaces. Those are the interfaces. Green means the classes. Okay. So the collection we have seen an interface inside that there are three different interface as well which is list Q and set. And since we are not able to create a reference variable of interface we need some classes. What are those classes? Array list, link list, vector stag. These are the classes which implements the list interface. Similarly there is a Q uh DQ is a interface which use array DQ. Similarly priority Q is also there. Then there is an interface which is known as set which uh imple the classes are hash set link set and one more are sort set which is a type of interface. So this is the collection hierarchy. So if I wants to create a list type then we are going to use array list link list factor new will be used there and the reference we can create using list as well. So what if there are function is provided in the collection interface all functions we can which are present in this list also in Q also in set. So that's why the functions which is provided by Java is inside the collection interfaces. What are those adding, removing? We will cover this uh later on. We have seen one example here only which is add functions. We have added some data. Similarly, there are more functions which is provided by the collection interface that will goes to the child which is array list as a child. Right? So automatically so uh let's understand the list hierarchy since we have understanded the list hierarchy. So uh list hierarchy have some points which you needs to know such that it is a ordered collection that means insertion order is being preserved here. That means uh like this we have seen I have added AJ then Rahul then Zara then Ankit in the original list you will see the insertion order is being preserved. Whatever I have inserted in manner line by line everything line by line has been inserted into that list. So this is known as ordered collection. Second is allow duplicates. That means intentionally let's say I have added a J two times. So let's check the result. You can see uh in original list AJ AJ is ping in two times that means it is accepting the duplicacy. So this is the second point inside the list that you should have and what are the implementation class array list link list vector we have used which implemented class array list class. So new keyword will associate with this class only and we are going to create a references of the interface like we did in the uh selenium. We are going to use a new chromedriver, god driver. These are the interface uh these are the classes which is implemented the interface of web driver class like we did. See driver is equal to new chrome driver. If I wants to create a open the chrome driver then I'm going to provide a new chrome driver in let's say if I want to run the firefox driver. This is how we can do same ideology me associated with it. So this is what uh we wants to know about the list interface hierarchy. So uh we have seen one example already which is uh array list where we are adding some datas and we are printing those values that is being already been done here. Then let's move on to the second one which is set. So uh set has a similar ideology when we are understanding in the math. In the math there is a concept of set. Set can accept the uh sent in set basically insertion order is not preserved. First one except lane stag shape. There is no duplicacy allowed. For example, instead of list, let's make it this as set. Since uh the set is not present which are the implemented class you can see headset linked headset and tree set those are the implemented classes. So let's say I have created headset. Let's uh import those classes. You can see these adding was there. Let me just remove unnecessary code. So you can see I have created one set with the name and we are adding all those values. You can see these are the duplicates I have added. You can see it is only adding one time. So this is the difference between set and the list. List is accepting duplicacy but set is not. Similarly let's say Rahul intentionally I have added AJ first then Rahul then Zara and then Ank. Let's check the order of the printing. You can see it is printing Rahul first then Zara and then AJ and then Ankil. any randomized order is it is print deserving. So it is not preserving the insertion order like we did in the array list. So this is the second difference between s list and a set. These are the interview question that you should have an expected ordered. What are the implemented class set link and s set? We have seen example of headset only. Uh we have already understand the programming logic how we are adding the same same thing needs to be done. So the Q will cover uh basically Q doesn't uh bother about much your major focus on the list and set that we already have an idea the basic idea how we are implementing all those values how we creating the same. So let's move on to the one more topic which is not present in this hierarchy. So there is one more topic which in has been uh so uh those who wants to uh basically interface let's say there is a map interface hierarchy was present here see uh map is basically another topic in the Java collection but not a hierarchy of the collections. Okay. So in the map interface uh key value pairs in associated where we can have a unique keys only every keys uh is not allowed to duplicate multiple key like we did in JSON. In JSON let's say you wanted to store some datas with the email and email this is not present because key cannot be same data can be same but key cannot. So this is the main difference we are going to cover later on. See uh examples we will cover this later on uh in the Java corrections topic when we're moving forward as well. So the only for we are going to deal with the implemented class which is hashmap linked hashmap and tree map. So these are the common thing that you should have an idea about the topic. So let's move on to the next topic which is a common collection method that you should have an idea with the help of uh Java since we have understanding such that collection is an interface right so if any method which is present in the collection interface those methods will come to list those method will come to set similarly if it comes to list set it will automatically comes to the array list link list vector stack so similarly like set has set links set preset so all those method can be used here automatically so same thing let's say so if I understand the logic of corrections methods then we going to understand the implemented class logic here so let's uh go one by one to understand uh the programming topic about the uh collection methods so let's understand using one Java program for this one that we uh create one class with the name of common collection methods. So this is the class I have created. You can see uh let's say intentionally I have created one list. Okay, let's say it is of string type test cases equal to new add list. Now this functions like first is add method. Let's understand the what is add method. Add method is description mean add a single elements. If you want to add a single elements we are going to use a uh add method. So let's these are the first thing that we need to do. test. So let's say main method test cases dot add login test. I have added one method for example. So guys uh let's say I have added one more which is signup test. These are the uh two uh variables I have added inside that uh list. Similarly if I want to add one more I have created intentionally one more list. Let's say more test more test. So in inside that mode test let me add some test for example API test mode test dot add UI test. So if I want to add this more test in this list as well. How we can do that? There is a function which is provided is add all. This is in this we can provide a complete list as well. So how we can do that? Let's say I wants to add this collection of more test. This is how we can completely add this list into this. So in if I print this test case, what does it print? All test cases. It will print login test, signup test, API test and UI test as well because we have directly added we have directly added complete mode list and login test as well. You can see login test, signup test, API test and UI test. This is known as adds and add all function that we have seen in this. Let's move on to the one more function. Uh so the function first let's check with the contains. So contains check if the element exist or not. Let's say I want to check if the login test is uh present then we can just print login test is present on this value. So how we can do that contains method is being used. So if test cases dot contains what what I I want to check I want to check this if it is present then we going to print sign up test is present all collection. So let me just uh print the output to check if it is present or not. You can see signup is present in Java in array we needs to run the loop then only we have checked the contains method. Same thing will happening with the only predefined function which is contains function intentionally let's say I have added a signup test. So this is not present. So this line of signup test is not present will not been shown to you. Okay, this is the difference between the contains or this is the use of the collection because it has predefined function that you are going to use directly. Let's say I wanted to print the size. How we can do that? Predefined function is is size. So size of test cases test cases dot size. So it will print the size of the this value 0 1 2 3. So it will print four. Okay. This is how the size will look. Let's say I wanted to remove some value inside that test case dot remove. If I want to remove this sign of test, if I want to remove this test and after this let's say uh print the value what does it print? remove this function. So after removing it will print login test, UI test and API test. These are the values that it's going to print. You can see these are the four values it is present. Similarly, four is being you can see I have removed the signup test. Now the it will contain three values only. This is how the remove function will use. Similarly, if I want to remove complete more test this list all all together, then how we can do that? Remove all function test cases dot remove all and more test. If I remove more test that means I removing this API in UI test. In the end, if I print this, it will only have the login test available in the output. You can see this is the we have discussed about some functions which is predefined in the collection interface that is being used in the uh array list directly. Add function we have understood. Similarly, we have understand the add all where we are directly adding the complete list. Then we have checked the contains means verification of that uh element is being present or not. So this can be used as well in automation perspective. What we can use? We can store the list of web elements and use contains function if to check if the web element is present on the web page or not. Similarly, we can get the size as well. If I want to remove some web element, we can use this function. If I remove all the web element which is innecessary we can use directly we remove all functions. So these thing can be reused in the automation perspective that's I wanted to tell you about it. So uh that we have seen. So same coding example I have seen here. So in the summary let's uh summarize the topic because everything is now uh done. I hope you are able to understand today's topic. So summary here is Java collection is powerful data handling. We have understood about it. right collection type for the use cases. uh we'll be do doing this side later on when we are doing the automation thing useful in test data management result storage dynamic test flows everything since uh array is for uh static it is used for dynamic thing most of the time in automation everything is dynamic so that's why we are going to use Java collections a lot of time in their realtime perspective so that's all for today's guys uh I hope you are able to understand today's lecture so let's meet on uh tomorrow about the second lecture with the Java collection associated with it. So, I hope you are able to understand it. Uh let me know into the chat section. Thank you everyone. Bye-bye.