Spring Boot Interview Mastery 🔥 | Question & Answer Guide for Developers | Part-3 | @Javatechie

hi everyone welcome back to Javi so today we'll dive into part three of our in-depth spring boot interview QA series but before we get started if you have not checked out part one and part two video be sure to do that for a solid foundation okay all right so without any further delay let's get started [Music] so let's begin with our first question that is how will you resolve be dependency ambiguity okay so this is one of the favorite interview question for experiened developer so first let's understand what is this Bean dependency ambiguity then we'll go for the solution okay so let me go to my intelligent idea so to demonstrate this ambiguity error I have an interface called order repository you can see here and I have one implementation class called order repository impl 1 okay next I have created another service called Trailer Service and I have injected the interface directly now if You observe this order repository is nothing my interface and I have only one implementation class called order Repository imp so that is the reason if I'll just inject the interface spring will understand okay this interface have only one implementation so I can directly inject it but what if this order repository interface have two implementation method or two implementation class order repository IML 1 let me comment this out order repository impl 2 now this single interface order repository have two implementation called order repos itl 1 and two now in The Trailer Service I have injected the interface now here how spring or spring boot framework will know which implementation class you want to inject here you have directly given the reference of interface it have only two implementation which implementation class you want to inject here how spring will know so let's run it we'll find out the error then we'll go for the solution okay so let me run it so we got the error if you read this carefully order repository in this Trailer Service required a single bin but two are found it means it is found two bin which is implementation one and implementation two can you see here those are the bin so this order repository having these two implementation so that is the reason this particular class is crying right so you need to tell to the spring framework which implementation class you want to inject here how you can tell that very simple there is a annotation called qualifier and in this annotation you just need to define the bean alas which one you want to use you want to use the implementation one or implementation two just copy the bean name and just Define here make sure to have it camel case okay now here I'm telling to the spring framework hey Spring I want to inject the implementation two class of this particular interface now if I run the code let's see whether we are getting the error or not so here application is getting up without any failure right so to avoid the bin dependency ambiguity you need to play with the at theate qualifier annotation okay so interviewer can directly ask you what is the real-time use case of at theate qualifier annotation or he might ask you how do you resolve the bin dependency ambiguity okay so for both the question the answer is same you just need to Define The annotation and you just need to tell to the spring which implementation class you want to inject okay that is straightforward now let's move to the next question that is can we avoid this dependency ambiguity without using qualifier is this possible to do in Spring framework yes absolutely we can do that so let me tell you there is a another annotation given by Java itself that is at the rate resource okay you can observe here this annotation came from java jakra do annotation okay now here the same thing you just need to define the B alas name which implementation class you want to use for example I want to use the impl one okay I don't need the qualifier annotation because I found find out the alternative that is at the rate resource so let me run it and we'll see whether it is working or it's giving the error so application is up there is no error it means you can avoid the be ambiguity either using at the rate qualifier or using at the rate resource so the basic difference between these atate qualifier and resource this atate qualifier annotation specific to the spring framework library and this resource annotation is given by Java Library itself okay and apart from that this qualifier annotation used the by type okay by class type but this atate resource annotation use by name okay that is the reason we are giving the name here so type of injection is by type in this qualifier and here by name okay so this is what the basic difference between atate resource and at theate qualifier Now using both we can avoid the ban ambiguity fine now let's move to the next question that is what is Bean scope and can you explain different type of bean scope this is another favorite interview question so we'll not go with the theory we'll try to demonstrate each Bean scope with practical example okay okay so let's first understand what is Bean scope then we list down all the supported Bean scope in the spring framework then we try to demonstrate that with example so Bean scope refer to the life cycle and visibility of a spring Bean within the ioc container or we can say Bean scope determines how long a bean instance will live and when it will be created or destroyed it's all about the be life cycle to just determine how long your bean will be alive and when it will be destroyed okay so there are different type of bean scope available in the spring framework singl ton prototype request session application and web soet okay so out of these six bin scope request session and application only applicable for web- based application but single ton prototype and web soet can be applicable for Standalone and web base application so this web suet and application Bean scope has been introduced in Spring framework 4.0 version onwards okay but before to that there are only four type of be scope single turn prototype request and session so let's go to the each be scope and let's derive it further so let's begin with the single T so the single T scope if you define your bean scope as a single T then spring boot or spring framework creates a single instance of the beIN for the entire application context and this is the default scope for a spring bin and the same instance will be shared across all the client requesting to that bin for example if I have defined the bean as a single ton let's say I have defined a test bin with the scope single tone then in my application context it will create only a single object of my test Bean okay so to demonstrate that let me go to the IDE then just open this particular class Bean scope test service so I have created a bean with the name Bean scope test service and I have just defined The Stereotype annotation at theate component now since we just understand by default every Bean scope is single ter so you know need to explicitly Define The annotation like scope and you don't need to Define like this okay so this way you can do do that since the default scope is the single T this is not required fine now let's try to instantiate this particular bin multiple times then we'll see how many times it is getting instantiate so that is the reason I have just added a statement in the Constructor fine so let me take this class name go to the main class then here simply I'll do context. getb of or I'll just Define the class name now I'll create it multiple time multiple time I'm asking to the spring to give me the object of this particular class now since it is the single ter let's see how it is behaving to us three I'm just trying to get the bin three times of this particular class now let me run the code we'll see how many times this Constructor is getting executed so let me rerun it so it is started now can you see here be scope test service instance created now if I'll search the statement since I have created object three times I should get three response right let me filter it out not here in the console how many times the occurrence is one so only one statement it is printing right so it clearly states that if you have defined the bean scope as a single T it will only create a single instance in your application context now going forward if you will request for that particular instance spring ioc container will get that instance from in memory rather than create a new one that is what the purpose of defining the be scope as a single turn okay now let's move to the next Bean scope that is prototype now let's take the example of of the same class now this class Bean scope test service we have defined the scope as a single ter but I want to Define this Bean scope as a prototype now what will happen so if you define the scope as a prototype it will always create a new instance of the bin every time you request to Spring context for example if I'll just Define prototype now since I want to customize the bean scope I have defined the annotation at theate scope and prototype but if it is a single turn you can skip that part now I have defined the bean scope as a prototype and I have created The Constructor and I'm just printing it so just to understand if you define the beIN scope as a prototype as many times you'll request for the object spring will create a new object for that particular bein so we'll verify it right away now if I run this I should observe three Constructor statement in the console now let me run this and we'll verify can you see here the console output let me Zoom this for you be scope test service instance created so I have requested to get the three instance and I'm getting it so this clearly states that if you define the B scope as a prototype it will always create a new instance if you request to the application context but single turn is just reverse it will just create only a single instance throughout the application okay so I believe these two bin scope is clear for you now let's move to the next one that is request Bean scope okay so first of all this request Bean scope can be used only in the web based application and it always creates a new instance of The Bean for each HTTP request after processing the request the ban instance is typically discarded okay so for example let's go to the yeah so I have defined something called request scope bin can you see here so I have just created a simple bin called request scoped bin and then I have annoted at theate scope and I have just defined the scope name as a request and I have just defined the proxy mode okay as a target class so the proxim mode attribute is necessary because at the moment of the instantiation of web application context there is no active request so what spring does it create a proxy to be injected as a dependency to this particular bin so that is the reason we just need to Define this proxy mode and apart from that the logic is very simple I have just Define a message and I have just hardcoded the message in my Constructor and even in Constructor I'm just printing the value okay now this particular request scope being I'm trying to access from my controller okay so let me comment this out because we understand right this request scope bin and session scope bin can be only tested in the web based application so that is the reason I'm just creating a simple Constructor and I'm just injected it to just call that particular instance through the web app fine so now I'll just do request scope bin dot get message something like that so what we understand if you define the request scope B if you define your bin scope as a request then each and every HTTP request will instantiate a new object of your request scope beingin so that is the reason I will trigger couple of request HTTP request and then we'll just verify whether the Constructor is getting called that many times or not okay that is how we can validate so what I can do I'll just restart it so application started now let me clear this console so what I'll do I'll just trigger the endpoint okay this one SL messages let me copy this okay go to the browser let me trigger it I trigger one time two time 3 4 5 6 7 8 9 10 okay 10 times I have triggered now we just need to verify for my each HTTP request what I have triggered is that many number of request C being is getting created or not okay can you see here 1 2 3 4 5 6 7 8 9 10 as many as HTTP request you will trigger since the scope is request scope it will create that many object of that bean that is that is clear from the statement right so for the simple statement this particular Bean scope will helps you to to store some data specific to the HTTP request okay such as kind of form data so in that scenario you can go for the request scope bin okay now let's move to the next one that is session scope so to demonstrate the session scope first of all the session scope is also can be performed in the web based application okay and if you define the bean scope as a session it creates a single instance of The Bean per user session so request scope create per request but the session scope will create per user session till the user logged in that particular instance will be there once he logged out that instance will be destroyed and once again if you request then it will create a I mean once again if you'll trigger the session again then it will create another bin so I I will prove that with some code so I have created a class called session scoped beIN right so let me go to that class so here is the class session scoped bin now if You observe here Ive did the same I have just Define the bin and just Define the scope which is session and I have just enabled the proxy mode and I'm just printing the messages I mean this message does not help I just want to show you the Constructor statement to just verify when the object is getting created okay or how many times is getting created at what use case so we have defined the Constructor and we have just added the state that's fine so what I'll do I will call this session scoped B from controller okay so I'll just comment it out and I will just enable it okay fine so this bin I have injected and I have just getting the I'm just calling the method that's fine so if I'll start my application session will be created and it will create one object so I need to also kill the session to validate this particular Behavior right session scoped bin until unless I will not stop my application or user is not logged out the session will not closed how can I demonstrate here so for that to forcefully close the session after 1 minute what I have done in the application. properties file I have just defined this server. session cookie Max is 1 minute and time out after just 1 minute so I'll just start my application then after 1 minute I will initiate another session and we validate whether the object is getting created per session or not that that is the simple right so that's fine what I'll do I'll just start the application so let me clear the console fine so I'll just copy this I'll open in a incognito mode I'll trigger the request we got the response and the Constructor is getting called correct now we'll wait for 1 minute then we'll retrigger the or we'll initiate another session to validate whether per session again Constructor is getting called or not okay can you see the time stamp 1154 now let's wait for one more minute 101 not 1154 yeah so 1 minute is completed now let me go to the browser I will copy this I will close this session and I will initiate the another session let me send the request we have triggered the request right I mean we have initiated another session now just verify can you see here 13 10 13 now let's say I will continue triggering the request from the same session it won't create the object because that object is already wind up with the session okay I mean the session scope so once the session will be killed after 1 minute I mean that is what we have defined in properties file then if you reinitiate the session it will create object per session okay this is what the session scope and if you think about the real time use case of the session scope so let's say you want to keep some user specific data to the session object then you can play with the session scope or if you want to go with the user authentication info to keep in the session you can also do that using the session scope okay now let's move to the next Bean scope that is application okay so this application scope is used in webbase application to create a single instance of The Bean for the entire web application context okay for your entire web application context it will only create a single object there is only one instance of the bin across all the users and sessions okay irrespective of request and session it will create a single instance throughout your web application okay and for example let's say you want to implement the application wide casing okay or if you have some shared resource you want to share throughout the application then you can Define the scope as a application scope I don't have any demo to demonstrate this application scope but this is something the key goal of this particular application scope now the last scope is web socet scope this web socet scope is specific to the web soet based application and it create a single instance of the beIN per web soet session okay again I don't have any project setup for web soet to demonstrate this be scope but this application and web soet Bean scope just understand this application scope will be create a single instance throughout the web application and this web soet scope is specific to the web soet session okay that's fine now let's move to the next question that that is how do you define your custom Bean scope first of all is it possible to define a custom Bean scope if yes how you will Define your own Bean scope so to answer this first let me walk you through one use case where I just want to create a instance for each thread okay it means for each thread I want to create a different be instance so how can I do that because single turn prototype request and session will not help so I need to create my own custom Bean scope so to create a custom Bean scope the steps are very simple you just need to play with the scope interface okay so I have created a simple class called um okay let me open that yeah custom thread scope okay I have created this particular class this class implements from scope so if You observe the scope is the interface and came from org. springframework dob Factory config okay and just Implement from scope and just override the method get method remove method register destruction call back resolve contextual object get conversion ID okay so the main two method is get the object from Context and remove the object from Context once you are done with it okay and this is what the call back and all I'm not going to explain that for now now since I want to create the object per thread so I have just created a thread local and Here If You observe in the gate method from the object Factory I'm getting the bean instance see this object Factory is something given by Spring framework right from the object Factory I'm getting the object of my beIN and then I'm adding to the map this map I have just created okay and then I'm just returning the object then once it is done I'm just removing the object from this particular map and see I'm just playing with the thread local fine that's simple right so you no need to worried about the code see the simple I'm using the thread local custom thread local I just created this class can you see here extend from thread thread local I and just Define the map and returning the empty map so that I can add the object to the map and I can remove the object to the map once the thread execution is completed okay cool now I want to implement this scope how can I do that to Define your own custom scope you need to again use atate scope and the name of your scope so to just Define a bean with this particular scope what you can do let me open a bin I have created this bin okay so I have just defined the scope name as a thread scope so atate scope and thread scope but how spring will know this is what some scope I need to register spring won't understand your scope right inside that if I write something XY Z or something like that how spring will understand the there is a scope with this particular name no right you need to manually registered in the spring context hey this is what the scope I'm using and this is what the class for that particular scope so if you'll go to the main class there you need to register your bean scope okay like this you need to register so I'm just creating the object of my thread scope and then context. get bin Factory do register the scope with what name you want to register and just give that particular object so same name you need to annotate here with atate scope now to just demonstrate for each thread it will create the object so what we can do go to the main class and then let me comment out this piece of code so if You observe here I I have just created a thread child thread and I'm creating two object of volunter okay so I'm creating two object so and then I'm just printing b1. code and b2. code it should be same because it is executing part of a single thread I'm creating two different Bean but it is part of a single thread so it should give me the same object right similarly I have created another thread which is I mean main thread and there also I'm creating two different being of this particular volunteer class who annotate the scope with thread scope okay so thread scope means it should create a single object per thread so it should create a single object for this thread and single object for this thread here also I'm just printing the hcode Okay so what I'll do I'll just run the code and will validate it should create two object one for this child thread one for this thread okay we can identify from the house code it should be different for two different thread for child and for main can you see here for child thread the object is same even though we have created two volunteer object but we are getting the same instance can you see from the house code when I tried with the main thread I'm getting different object since I have tried two times in the main thread it will only give me the same reference so one object for child one object for main thread okay this is how you can Define the custom Bean scope if needed I mean I have just covered one use case you can try out couple of use case to just Implement your custom Bean scope fine now let's move to the next one can you provide a few realtime use case for when to choose single turn scope and prototype scope this is one of the hot interview question if you are a spring developer interviewer will definitely ask you what is the difference between Bean scope single turn and prototype when you will choose single turn over prototype like that you can find multiple question so let me explain in details so first of all the choice between using a single turn or prototype scope for a v in a spring application depends on your specific use case and the behavior you require for those beans so let me list down couple of realtime use case so there are couple of use case for single T and prototype so you can go for this scenario you can go for single ton scope database configuration service layer application configuration when is when I say for database configuration you can go for single turn scope for example your config configuring a database connection pool or cashing mechanism then you typically want a single or shared instance across the entire application right which will ensure that all part of your application use the same database connection or cash so in such scenario you can go for Singleton bin I mean you can create your own database configuration with the scope single turn bin okay next service layer so again if it is a stateless service or component that do not maintain any mutable State using a singl ton scope is efficient for that so this service can be shared across multiple request without any issue okay so you can also use the service Us in the service layer if it does not contains any mutable state next application configuration let's say you have a beIN that stores configuration settings or application wide constant that can be defined as a single turn because these settings are constant throughout the application lifetime okay so if you have some such kind of scenario to having the uh constant throughout the application then you can go for the single turn Bean scope next let's understand couple of point from the Prototype scope the first point is user session in web application objects that need to maintain the state specific to the user session should use prototype scope so in the web application you want to keep the user specific session into a object and you need every time if the user logged in or triggered the session you want to create a different object okay specific to that particular user session then you can go for Prototype scope then the next point is thread safety if a beIN is not thread safe and multiple threads need to use it concurrently using prototype scope we can ensure that each thread gets its own instance because we know prototype as many times you will request you will get different instance this can be important for object like parser or Builder that maintains internal State okay so For Thread safety you can go for Prototype now if you have something if you have some logic which will be heavy initialization okay when creating object with expensive initialization or resource allocation you might prefer prototype scope this way you can dispose of the object when it's no longer needed and you can avoid the resource leaks okay so for this kind of scenario you can go for Prototype scope so in summary I have just explained at high level but the choice between single T and prototype scope depends on couple of factors such as statefulness thread safety object life cycle and Resource Management so you need to analyze the specific requirement of your component and then Behavior within your application to determine which scope is most appropriate for use your use case Okay so that is how you can identify what needs to be used fine now let's move to the next question that is can we inject a prototype bin into a single T bin if yes what will happen if we'll inject a prototype bin into the single turn beIN okay this is another common interview question so we'll understand it with various approach first we'll understand what is the problem then we'll understand how we can overcome it okay so let me walk you through an example then you'll get the complete Clarity okay so let's go to the project I have created a bean called Singleton bean and I have created a bean called prototype Bean you can see the scope of prototype Bean right prototype and in single T bean I have injected the Prototype Bean can you see here in the single turn bean I have injected this prototype Bean now how it will behaves because we know single T Bean means it will only create a single instance on the time of class loading right or application context loading then whether it will create multiple object of this prototype b or it will create a single object of the Prototype bean I mean whether this prototype Bean will behave as a prototype scope or single turn scope so we'll verify that then we'll find out the solution if required okay so to the clear statement if you inject the Prototype ban into a single turn bin it will behave as a single turn it will lose its own scope because it is injected to the bin which is single turn Okay so first let's verify it in single turn I have prototype and I'm just trying to get the instance of it to just print the house code whether it is same or different okay so go to the main class we understand these things right let me comment this out otherwise there will be lot of log statement in our console let me comment this out okay so what I have done here I getting the I'm trying to getting the bean of single T So once I will get to different single T instance then I'm just trying to get the Prototype bin instance and just wanted to verify its has code okay I getting the single turn instance then from the single turn instance since I have injected the Prototype being see observe here I have injected this prototype Bean into this single turn Bean I'm trying to validate whether it is creating multiple prototype Bean or not okay because the scope we have defined prototype so let me run it then we'll verify can you see here the console If You observe it is creating a single instance of prototype B this is wrong right because this particular prototype being class is losing his own beIN scope because he want to be always create a new instance as for the beIN scope but since we have injected to the single turn it is not creating the multiple object so for example if I'll change it let's say I'll just change the single turn B to prototype okay now if I rerun the code it will create multiple object because there will be no restriction okay so let's verify that then we'll find out the solution how we can overcome it can you see here if I will Zoom this for you both are having two different has code this works because I have defined the I have changed the scope okay but that is not what our question I just added this to demonstrate how it is behaving if you'll inject a prototype bin into a single turn B this will also beave as a single turn that's what we identify from the console output now how we can overcome that then that's very simple so there are multiple approaches let me go one by one so you can use application context you can inject that and you can comment this because I don't want to inject through Auto otherwise it will be as a single turn so what I do while getting the bin I just return return context. get bean of class name prototype Bean do class okay this way we can do but again manually we are getting the bin manually we are trying to maintain the bean life cycle not by the spring so this approach is not recommended but this will work for now let me run and I'll will show you so here I should get two different has code because I'm telling to the this particular class I'm telling get the B from the context not here here right every time get the bean from the context because this beIN scope is a prototype can you see here in the output are you getting two different has code it means it is creating two different object fine now let's try with the another approach instead of application context you can also use there is some class called uh prototype um object Factory or something like that private object Factory then just Define the class name for what you want to create the object spring will take care of it okay just Define the class name and then you can simply do prototype Factory dot get the object for me fine now let me run this we should get two different has code because we are just following the correct Bean scope right because if something is injected to the single T Bean if some Bean whose scope is prototype is injecting to the single turn Bean then it should behave as it is right it should behave its own scope can you see here we got the two different has code fine there is another approach which is straightforward what you can do you can write a method let's say public who will return me the Prototype bin then simply just return null and on top of this particular method just annotate look up okay this is what The annotation given by Spring framework to play with this particular kind of conflict so this particular injection what we are doing now will be considered as a lookup method injection okay so here I'm just returning the n I'm not creating the object of prototype B now who will create it for me then behind the scene spring will create the proxy for you proxy for this particular bin Dynamic proxy so you just need to use this method name get instance okay every time you will request spring will come to this method and will'll create a new object for you because you have Define the B scope as a prototype fine let me run it and we'll verify whether we are getting two different house code or not so if You observe here we are getting two different has code fine so this is how you can avoid this kind of conflict regarding the bean scope single turn and prototype and vice versa okay that's fine now let's move to the next question that is what is the difference between spring single turn and plane single turn if if you remember in Java also we have something called single turn design pattern to get only a single instance per jvm right but in Spring single turn we are getting a single instance per application context so in simple word interviewer will ask this question to confuse you but make sure to give the answer that spring single turn scope within the application context and plain singl turn scope within the jvm so in Spring if I'll create two different application context and from two different application if I'll try to get the instance of single turn bin then it will give me two different instance because it scope within the application context but in Plaine single ton I mean in Java single ton you will get only different instance if it will run into different jbm okay that is the straightforward answer now let's move to the next question what is the purpose of being post processor interface in Spring and how can you use it to customize bin initialization and destruction this is another important question to check your understanding on Spring core module because this being post processor is something play the critical role in Spring core module okay so we'll demonstrate with an example so first of all in Spring framework being post processor is an interface that provides hooks or call backs to perform pre-process procing logic when I say pre-processing logic it allow you to perform custom action on being before and after being initialization before and after your bean initialized if you want to customize something on your bean then you can perform this using Bean post processor for example let's say I want to create a bean let's say user bean and I setting some username and password something like that and I want to validate that credential and I want to validate that user bin before it initialize the value how can I do that how can I do such kind of validation before the be initialization or after my be initialization for example I'm talking about the same use case let's say I'm just creating a bean of user okay let me comment it out so if You observe I'm creating the bean of user but while creating this particular Bean while initializing this particular value to this particular user bin I just want to validate the password okay so before initialization itself I want to validate the password how can I do that simple right post processor is there to help here so I have created a class called validation post processor okay so if I'll open that password validation post processor who implements from being post processor as I already men this is an interface and it contains two method read the method name carefully you'll understand the purpose of each method post process before initialization post process after initialization before initialization of your bean if you want to do something play with this particular method after initialization Bean if you want to add some logging or monitoring the uh Bin then you can play with this particular method this is for before initialization this is for after initialization so if You observe in the code I'm not doing anything I'm just validating the password I have created a method to just check the regular expression to validate the password so since I want to perform before initialize my beIN I want to validate that password so I'm getting the instance of user then I'm just calling the I mean the method private method I have created to validate the password if it is wrong it will simply throw the exception with this particular message I'm doing this okay this is what I'm doing in the before initialization phase so if you try to understand at high level when it will create the be of user and when it will initialize this particular value at application startup immediately control will goes to this particular post processor implementation class and then it will execute if you have something before initialization and then if you have something after initialization so let's run the code we'll validate whether it is giving us the error or not because even though we have provide the wrong password this validation being post processor is working or not before initializing is validating my b or not okay so let me run the application can you see here we are getting the error message invalid password for user John so I have just taken the example of Domi class which is user but in your project you can validate your actual bin which you used in real time for example you want to validate something kka template right if it is secured or not if it is having the expected parameter or not or if you're getting a user request you want to validate that so you can play with this Bean post processor apart from that there are couple of use case you can go for the be post processor cess for example you want to modify or adding properties to a bin after it's created or before it's created or you want to automatically adding the aspect to the Bean or you you want to execute some custom code during the initialization phase so in currently in the custom phase I mean the initialization phase we are just creating a bean but you might need to add the monitoring and logging right so that time also you can go for bin post processor or if you want to create the dynamic proxy for the bin for various purpose also you can go for be post processor there are couple of use Cas you can find out to use this be post processor okay that's it for part three of the video I'll be presenting more advanced question in the upcoming part four video in the meantime please review and practice the skills covered in the previous interview QA video that's all about this particular video guys thanks for watching this video meet you soon with A New Concept

Channel: Java Techie

Views: 33,801

Keywords: Spring Boot Interview, Spring Boot Interview Questions, Spring Boot Interview Answers, Spring Boot Interview Preparation, Spring Boot Tips, Java Spring Boot Interview, Spring Framework Interview, Java Interview Questions, Java Interview Tips, Spring Boot Hands-On, Spring Boot Tips and Tricks, Spring Boot Interview Techniques, javatechie, spring boot

Id: XfScG87YSHQ

Length: 47min 2sec (2822 seconds)

Published: Fri Oct 13 2023