Reid  Rohan

Reid Rohan

1637284140

Top 5 Trickiest JavaScript Interview Questions

Are you a front-end developer looking to switch jobs and are you contemplating the possible tricky questions that one might ask? Or are you a senior JavaScript developer who’s looking for interview questions that could sound a little tricky? Fret not, read further if both the above-mentioned questions apply to you (or if you’re just a JavaScript nerd who is curious to know what my definition of tricky is, please be my guest).

I’ve just made a compilation of all the possible questions that I or my friends, that take interviews, find tricky.

To start with, always remember there’s no such thing as tricky. If you’ve got your basics right then any question asked is just twisted English that is meant to scare you off.

1. The hawk-eye test

2. Hoisting

3. Closure

4. The classic — this

5. Array length

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Top 5 Trickiest JavaScript Interview Questions

Top 130 Android Interview Questions - Crack Technical Interview Now!

Android Interview Questions and Answers from Beginner to Advanced level

DataFlair is committed to provide you all the resources to make you an android professional. We started with android tutorials along with practicals, then we published Real-time android projects along with source code. Now, we come up with frequently asked android interview questions, which will help you in showing expertise in your next interview.

android interview questions

Android Interview Questions – Get ready for your next interview

Android – one of the hottest technologies, which is having a bright future. Get ready to crack your next interview with the following android interview questions. These interview questions start with basic and cover deep concepts along with advanced topics.

Android Interview Questions for Freshers

1. What is Android?

Android is an open-source mobile operating system that is based on the modified versions of Linux kernel. Though it was mainly designed for smartphones, now it is being used for Tablets, Televisions, Smartwatches, and other Android wearables.

2. Who is the inventor of Android Technology?

The inventors of Android Technology are- Andry Rubin, Nick Sears, and Rich Miner.

3. What is the latest version of Android?

The latest version of Android is Android 10.0, known as Android Q. The upcoming major Android release is Android 11, which is the 18th version of Android. [Note: Keep checking the versions, it is as of June 2020.]

4. How many Android versions can you recall right now?

Till now, there are 17 versions of Android, which have their names in alphabetical order. The 18th version of Android is also going to come later this year. The versions of Android are here:

  • Android 1.0 – Its release is 23 September 2008.
  • Android 1.1 – Its release date is 9 February 2009.
  • Android 1.5 – Its name is Cupcake, Released on 27 April 2009.
  • Android 1.6 – Its name is Donut, Released on 15 September 2009.
  • Android 2.0 – Its name is Eclair, Released on 26 October 2009
  • Android 2.2 – Its name is Froyo, Released on 20 May 2010.
  • Android 2.3 – Its name is Gingerbread, Released on 06 December 2010.
  • Android 3.0 – Its name is Honeycomb, Released on 22 February 2011.
  • Android 4.0 – Its name is Ice Cream Sandwich, Released on 18 October 2011.
  • Android 4.1 – Its name is Jelly Bean, Released on 9 July 2012.
  • Android 4.4 – Its name is KitKat, Released on 31 October 2013.
  • Android 5.0 – Its name is Lollipop, Released on 12 November 2014.
  • Android 6.0 – Its name is Marshmallow, Released on 5 October 2015.
  • Android 7.0 – Its name is Nougat, Released on 22 August 2016.
  • Android 8.0 – Its name is Oreo, Released on 21 August 2017.
  • Android 9.0 – Its name is Pie, Released on 6 August 2018.
  • Android 10.0 – Its name is Android Q, Released on 3 September 2019.
  • Android 11.0 – As of now, it is Android 11.

5. Explain the Android Architecture with its components.

This is a popular android developer interview question

Android Architecture consists of 5 components that are-

a. Linux Kernel: It is the foundation of the Android Architecture that resides at the lowest level. It provides the level of abstraction for hardware devices and upper layer components. Linux Kernel also provides various important hardware drivers that act as software interfaces for hardwares like camera, bluetooth, etc.

b. Native Libraries: These are the libraries for Android that are written in C/C++. These libraries are useful to build many core services like ART and HAL. It provides support for core features.

c. Android Runtime: It is an Android Runtime Environment. Android Operating System uses it during the execution of the app. It performs the translation of the application bytecode into the native instructions. The runtime environment of the device then executes these native instructions.

d. Application Framework: Application Framework provides many java classes and interfaces for app development. And it also provides various high-level services. This complete Application framework makes use of Java.

e. Applications: This is the topmost layer of Android Architecture. It provides applications for the end-user, so they can use the android device and compute the tasks.

6. What are the services that the Application framework provides?

The Android application framework has the following key services-

a. Activity Manager: It uses testing and debugging methods.

b. Content provider: It provides the data from application to other layers.

c. Resource Manager: This provides users access to resources.

d. Notification Manager: This gives notification to the users regarding actions taking place in the background.

e. View System: It is the base class for widgets, and it is also responsible for event handling.

7. What are the important features of Linux Kernel?

The important features of the Linux Kernel are as follows:

a. Power Management: Linux Kernel does power management to enhance and improve the battery life of the device.

b. Memory Management: It is useful for the maximum utilization of the available memory of the device.

c. Device Management: It includes managing all the hardware device drivers. It maximizes the utilization of the available resources.

d. Security: It ensures that no application has any such permission that it affects any other application in order to maintain security.

e. Multi-tasking: Multi-tasking provides the users the ease of doing multiple tasks at the same time.

8. What are the building blocks of an Android Application?

This is a popular android interview question for freshers.

The main components of any Android application are- Activity, Services, Content Provider, and Broadcast Receiver. You can understand them as follows:

a. Activity- It is a class that acts as the entry point representing a single screen to the user. It is like a window to show the user interface.

b. Services- Services are the longest-running component that runs in the background.

c. Content Provider- The content provider is an essential component that allows apps to share data between themselves.

d. Broadcast receivers- Broadcast receiver is another most crucial application component. It helps the apps to receive and respond to broadcast messages from the system or some other application.

9. What are the important components of Android Application?

The Components of Android application are listed below:

  1. Widgets
  2. Intents
  3. Views
  4. Notification
  5. Fragments
  6. Layout XML files
  7. Resources

10. What are the widgets?

Widgets are the variations of Broadcast receivers. They are an important part of home screen customization. They often display some data and also allow users to perform actions on them. Mostly they display the app icon on the screen.

11. Can you name some types of widgets?

Mentioned below are the types of widgets-

a. Informative Widgets: These widgets show some important information. Like, the clock widget or a weather widget.

b. Collective Widgets: They are the collection of some types of elements. For example, a music widget that lets us change, skip, or forward the song.

c. Control Widgets: These widgets help us control the actions within the application through it. Like an email widget that helps check the recent mails.

d. Hybrid Widgets: Hybrid widgets are those that consist of at least two or more types of widgets.

12. What are Intents?

Intents are an important part of Android Applications. They enable communication between components of the same application as well as separate applications. The Intent signals the Android system about a certain event that has occurred.

13. Explain the types of intents briefly?

Intent is of three types that are-

a. Implicit Intents: Implicit intents are those in which there is no description of the component name but only the action.

b. Explicit Intents: In explicit intents, the target component is present by declaring the name of the component.

c. Pending Intents: These are those intents that act as a shield over the Intent objects. It covers the intent objects and grants permission to the external app components to access them.

14. What is a View?

A view is an important building block that helps in designing the user interface of the application. It can be a rectangular box or a circular shape, for example, Text View, Edit Text, Buttons, etc. Views occupy a certain area of the screen, and it is also responsible for event handling. A view is the superclass of all the graphical user interface components.

15. What do you understand by View Group?

It is the subclass of the ViewClass. It gives an invisible container to hold layouts or views. You can understand view groups as special views that are capable of holding other views, that are Child View.

16. What do you understand about Shared Preferences?

It is a simple mechanism for data storage in Android. In this, there is no need to create files, and using APIs, it stores the data in XML files. It stores the data in the pair of key-values. SharedPreferences class lets the user save the values and retrieve them when required. Using SharedPreferences we can save primitive data like- boolean, float, integer, string and long.

17. What is a Notification?

A notification is just like a message that shows up outside the Application UI to provide reminders to the users. They remind the user about a message received, or some other timely information from the app.

18. Give names of Notification types.

There are three types of notifications namely-

a. Toast Notification- This notification is the one that fades away sometime after it pops up.

b. Status Notification- This notification stays till the user takes some action on it.

c. Dialog Notification- This notification is the result of an Active Activity.

19. What are fragments?

A fragment is a part of the complete user interface. These are present in Activity, and an activity can have one or more fragments at the same time. We can reuse a fragment in multiple activities as well.

20. What are the types of fragments?

There are three types of fragments that are: Single Fragment, List Fragment, Fragment Transactions.

  1. Single Transactions can only show a single view for the user.
  2. List Fragments have a special list view feature that provides a list from which the user can select one.
  3. Fragment Transactions are helpful for the transition between one fragment to the other.

Frequently asked Android Interview Questions and Answers

21. What are Layout XML files?

Layout XML files contain the structure for the user interface of the application. The XML file also contains various different layouts and views, and they also specify various GUI components that are there in Activity or fragments.

22. What are Resources in Android Application?

The resources in Android Apps defines images, texts, strings, colors, etc. Everything in resources directory is referenced in the source code of the app so that we can use them.

23. Can you develop Android Apps with languages other than Java? If so, name some.

Yes, there are many languages that we can work with, for the development of Android Applications. To name some, I would say Java, Python, C, C++, Kotlin, C#, Corona/LUA.

24. What are the states of the Activity Lifecycle?

Activity lifecycle has the following four stages-

a. Running State: As soon as the activity starts, it is the first state.

b. Paused State: When some other activity starts without closing the previous one, the running activity turns into the Paused state.

c. Resume State: When the activity opens again after being in pause state, it comes into the Resume State.

d. Stopped State: When the user closes the application or stops using it, the activity goes to the Stopped state.

25. What are some methods of Activity?

The methods of Activity are as follows:

  • onCreate()
  • onStart()
  • onPause()
  • onRestart()
  • onResume()
  • onStop()
  • onDestroy()

26. How can you launch an activity in Android?

We launch an activity using Intents. For this we need to use intent as follows:

  1. ntent intent_name= new Intent(this, Activity_name.class);
  2. startActivity(intent_name);

27. What is the service lifecycle?

There are two states of a service that are-

a. Started State: This is when the service starts its execution. A Services come in start state only through the startService() method.

b. Bounded State: A service is in the bounded state when it calls the method bindService().

28. What are some methods of Services?

The methods of service are as follows-

  • onStartCommand()
  • onBind()
  • onCreate()
  • onUnbind()
  • onDestroy()
  • onRebind()

29. What are the types of Broadcast?

Broadcasts are of two types that are-

a. Ordered Broadcast: Ordered broadcasts are Synchronous and work in a proper order. It decides the order by using the priority assigned to the broadcasts.

b. Normal Broadcast: These are asynchronous and unordered. They are more efficient as they run unorderly and all at once. But, they lack full utilization of the results.

30. What are useful impotent folders in Android?

The impotent folders in an Android application are-

  1. build.xml- It is responsible for the build of Android applications.
  2. bin/ – The bin folder works as a staging area to wrap the files packages into the APK.
  3. src/ – The src is a folder where all the source files of the project are present.
  4. res/ – The res is the resource folder that stores values of the resources that are used in the application. These resources can be colors, styles, strings, dimensions, etc.
  5. assets/ – It provides a facility to include files like text, XML, fonts, music, and video in the Android application.

31. What are the important files for Android Application when working on Android Studio?

This is an important android studio interview question

There are following three files that we need to work on for an application to work-

a. The AndroidManifest.xml file: It has all the information about the application.

b. The MainActivity.java file: It is the app file that actually gets converted to the dalvik executable and runs the application. It is written in java.

c. The Activity_main.xml file: It is the layout file that is available in the res/layout directory. It is another mostly used file while developing the application.

32. Which database do you use for Android Application development?

The database that we use for Android Applications is SQLite. It is because SQLite is lightweight and specially developed for Android Apps. SQLite works the same way as SQL using the same commands.

33. Tell us some features of Android OS.

The best features of Android include-

  1. Multi-tasking
  2. Support for a great range of languages
  3. Support for split-screen
  4. High connectivity with 5G support
  5. Motion Control

34. Why did you learn Android development?

Learning Android Studio is a good idea because of the following-

  1. It has a low application development cost.
  2. It is an open-source platform.
  3. It has multi-platform support as well as Multi-carrier support.
  4. It is open for customizations.
  5. Android is a largely used operating system throughout the world.

35. What are the different ways of storage supported in Android?

The various storage ways supported in Android are as follows:

  1. Shared Preference
  2. Internal Storage
  3. External Storage
  4. SQLite Databases
  5. Network Connection

36. What are layouts?

Layout is nothing but arrangements of elements on the device screen. These elements can be images, tests, videos, anything. They basically define the structure of the Android user interface to make it user friendly.

37. How many layout types are there?

The type of layouts used in Android Apps are as follows:

  1. Linear Layout
  2. Relative Layout
  3. Constraint Layout
  4. Table Layout
  5. Frame Layout
  6. Absolute Layout
  7. Scrollview layout

38. What is an APK?

An APK stands for Android Package that is a file format of Android Applications. Android OS uses this package for the distribution and installation of the Android Application.

39. What is an Android Manifest file?

The manifest file describes all the essential information about the project application for build tools, Android operating system, and google play. This file is a must for every Android project that we develop, and it is present in the root of the project source set.

#android tutorials #android basic interview questions #android basic questions #android developer interview questions #android interview question and answer #android interview questions #android interview questions for experienced #android interview questions for fresher

Sigrid  Farrell

Sigrid Farrell

1623718560

Top 10 Critical Spring Boot Interview Questions and Answers [For Beginners & Experienced]

offers powerful features for the rapid development of deployment-ready applications. It is the most used and best java framework for the development of scalable microservices and web applications.

If you want to become a domain expert, you have come to the right place. We have curated some the most repeatedly asked spring boot interview questions and answers to help you ace the interview.

Basic Spring Boot Interview Questions And Answers

Technical Spring Boot Interview Questions And Answers

Conclusion

#full stack development #interview question answer #spring boot interview questions answer #top spring boot interview questions #top 10 critical spring boot interview questions #answers

Justen  Hintz

Justen Hintz

1563350523

Top 50 Interview Questions for JavaScript Developer

Developer interviews are like the wild west. Nobody really knows what they’re doing. Most tech recruiters can’t distinguish between Java and JavaScript (thumbs up if you can). Yet somehow they’re tasked to recruit developers.

From time to time, we even get asked for eight years of Swift experience. Considering the Swift language is three years old, don’t let this stop you from applying.

Developer jobs are fun, challenging, and fulfilling. Getting past the interview can be as easy as flying through the door, or can be overly obnoxious to hellish whiteboard challenges. You never know what to expect.

Luckily, we as developers can prepare for all the technical parts and be sure to at least ace those. We never know what silly questions to expect, but at least we can be confident in our technical answers.

Most (modern) companies are waking up to the realization the developer interview process is broken and needs fixing. These are the companies we want to work for.

Without further ado, I gathered 100 questions that I think you should be able to answer before walking to a front-end developer interview.

General questions are questions to get to know you, how you react, think, and how well you fit in the team.

Keep your answers to these questions relatively short and concise, since they don’t carry that much weight.

Don’t trip over your words; take long pauses to think thoroughly about the questions. The questions are meant to “crack” you open so they can taste the yolk.

  1. What excites or interests you about coding?
  2. What did you learn yesterday/this week?
  3. Talk about your preferred development environment. Which Operating System, IDE, and Terminal do you use and why those in particular?
  4. If you could master one technology this year, what would it be? How would you go about mastering that skill?
  5. How did you handle the last disagreement with your direct boss? How did it resolve? Would you give me your boss’s number to check their side of the story? [The last question is a bluff, but be sure to not flinch. No one has the time to call your previous boss.]
  6. What resources, forums, or tools do you use to learn about the latest front end development and design trends? Any favorites and why?
  7. If you joined on a project and they [the dev team] used tabs and you used spaces, what would you do? Would you try to convince the team to use spaces or would you join the herd and use tabs?

[Trick question] — The most correct answer would be to use a standard format tool like Prettier, so everyone's code will look the same when it’s pushed to the repository. This way you can keep using spaces, and the team is free to use tabs.

If you force your opinion on the dev team, you wouldn’t be considered a team player, and if you used tabs without your full consent and reasoning, you wouldn’t be as motivated as everyone else and are more likely to quit.

8. Can you describe your workflow when you create a web page? What are the first five steps you take when creating a new project?

9. What is a recent technical challenge you experienced and how did you solve it?

10. What actions have you taken on recent projects to increase the maintainability of the code? Any particular programming paradigms you like such as functional programming or test-driven development?

Now that we’re past the general questions and chit-chat, it’s time for the showdown. This where the interview will start shooting technical questions at you.

Note: The questions are more focused toward front-end development but may include back-end, dev ops and problem-solving questions too.

11. Which version control systems are you familiar with? How do you share code between projects in a lossless way?

12. Name four ways to decrease page load.

13. What does CORS stand for and what issue does it address?

14. Explain what ARIA and screenreaders are, and how to make a website accessible.

15. What does a doctype do?

16. What are the building blocks of HTML5?

17. Describe the difference between localStorage, cookies, and sessionStorage.

18. What are data- attributes good for?

19. What kind of things must you be wary of when designing or developing for multilingual sites? How do you serve a page with content in multiple languages?

20. What is progressive rendering?

21. Explain how this works in JavaScript. How does this work in classes versus functions?

22. Describe event bubbling and event capturing.

23. Explain variable hoisting.

24. Explain the difference between:

  • function Animal() {}
  • var animal = Animal()
  • var animal = new Animal()

25. What’s the difference between host objects and native objects?

26. What’s a typical use case for anonymous functions?

27. Explain how JavaScript prototypal inheritance works.

28. What is a closure, and how/why would you use one?

29. What’s the difference between null and undefined?

30. What is the difference between == and ===?

31. What is Webpack? What problems does it solve?

32. Have you ever used a front-end framework or library? Which one?

33. Why is it called a Ternary operator; what does the word Ternary indicate?

34. What tools and techniques do you use debugging JavaScript code?

35. How do you debug JavaScript code that runs on the server, e.g. NodeJs?

36. What are some of the advantages/disadvantages of writing JavaScript code in a language that compiles to JavaScript?

37. Given this code, how would you implement the duplicate function?

// make this work

duplicate([1,2,3,4,5]); // [1,2,3,4,5,1,2,3,4,5]

38. Can you give an example of a curry function and why this syntax offers an advantage?

39. Can you give an example of destructuring an object or an array?

40. Who invented JavaScript and why is it called JavaScript?

41. What is the difference between these two functions?

// What’s the difference?

const sayHello = name => console.log(name)

function sayHello(name) {
console.log(${name})
}

42. Why and when might you want to create static class members?

43. What are the differences between variables created using let, var or const?

44. What happens when you go to a website? What’s a DNS?

45. What is the V8 Engine? Who uses it?

46. What does $ in JavaScript code refer to?

47. Explain the difference between layout, painting, and compositing.

48. What are some ways you may improve your website’s scrolling performance?

49. What is the output of the following code?

let fs = require(‘fs’);

console.log(‘1’);

fs.readFile(‘test.txt’, ‘utf8’, function(error, data) {
if (error) {
throw error;
}

console.log('2');

});

console.log(‘3’);

50. What is the event loop in JavaScript and what does it do?

If you knew the answers to most questions, well done!

Thanks for reading

If you liked this post, please do share/like it with all of your programming buddies!

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Further reading about JavaScript

The Complete JavaScript Course 2019: Build Real Projects!

Vue JS 2 - The Complete Guide (incl. Vue Router & Vuex)

50+ Java Interview Questions for Programmers

Top 100 Python Interview Questions and Answers

Top 100 Python Interview Questions and Answers

Best 50 React Interview Questions and Answers in 2019

Top 50+ SQL Interview Questions and Answers in 2019

Best 50 Nodejs interview questions from Beginners to Advanced in 2019

100+ Java Interview Questions and Answers In 2019

Best 50 React Interview Questions for Frontend Developers in 2019

Best 50 Angular Interview Questions for Frontend Developers in 2019

#javascript #web-development #interview #interview-questions

Top 5 Mobile App Development Companies in New York

New York is the best potential business hub for the technology and IT industry. Thousands of companies are established in New York for the mobile app development or technology industry. So, here quite a confusion is that how to choose the right company for your business amongst all the companies. No need to worry about it, We have found the most reliable and trustworthy mobile app development companies that are the top-tiers in New York. Before we share the companies list you need to know the benefits of mobile app development for your business.

Key Benefits of Mobile App Development:

· Improves Efficiency

· Offers High Scalability

· Secures Your App Data

· Integrates With Existing Software

· Easy to Maintain

· Improves Customer Relationship

· Facilitates New Client Data Retrieval

· Provides Real-time Project Access

Are you looking for top mobile app development companies in New York that help to create a custom mobile app as per your business requirements? Please go through these Top 5 mobile app development companies that provide exceptional development and design services for your business.

Top Mobile App Development Companies in New York:

1. AppCluesInfotech

AppClues Infotech is one of the leading mobile app development company based in New York that builds high-quality mobile apps. Being a versatile mobile app development company, they provide services on various platforms like Android, iOS, Cross-platform, Windows, etc. They are aware of the latest technologies and features of industry. They utilize them to create a user-engaging mobile app. They have the best team of designers and developers who are delivered a mobile app with high-quality and performance.

Founded In: 2014

Employees: 50 to 200 Members

Location: USA

Website: https://www.appcluesinfotech.com/

2. Data EximIT

Data EximIT is one of the leading mobile app development company in New York that provides top-notch and elegant mobile app development services with the latest market trends and functionalities at a competitive price. They have highly experienced mobile app designers and developers team who have the best strength of developing all types of a mobile app. They deliver a feature-rich mobile app for their clients that give the best business ROI.

Founded In: 2004

Employees: 50 to 150 Members

Location: USA & India

Website: https://www.dataeximit.com/

3. WebClues Infotech

WebClues Infotech is the most reliable & superior company that builds custom mobile apps to do things differently. They are the best mobile app development company in New York, USA and as well as globally with high proficiency. They have a highly experienced app developers team that has the best strength of work on multiple platforms like android, Cross-platform, and iOS.

They have successfully delivered 950+ mobile app projects effectively and on-time. Build your Robust, Secure, Scalable & High-performance mobile app with WebClues Infotech with creative & dynamic designs at an affordable price.

Founded In: 2014

Employees: 50 to 250 Members

Location: USA, INDIA, UAE, UK & CANADA

Website: https://www.webcluesinfotech.com/

4. AppClues Studio

AppClues Studio is a leading mobile app development company in New York, USA. The company is versatile in developing custom mobile app development solutions to its customers across the globe. With an experience of 8+ years in mobile app development, Utility is hyper-focused on Return on Investment (ROI) and building good relationships with partner companies. The company is worked with a start-up to large enterprises.

Founded In: 2014

Employees: 50 to 150 Members

Location: USA & UK

Website: https://appcluesstudio.com/

5. WebClues Global

WebClues Global is a prominent mobile application development company in New York, USA. They are one of the top-tier mobile app developers who deliver high-end Android mobile app solutions to their clients. The company operated with 100+ qualified developers who working in different domains to give the best solution for their development. WebClues Global offers various services including web and mobile design & development, E-Commerce Development, Ui/Ux Development.

Founded In: 2014

Employees: 50 to 150 Members

Location: USA, INDIA, UAE, UK & CANADA

Website: https://www.webcluesglobal.com/

#top 5 mobile app development companies in new york #top 5 mobile app development companies in usa #top mobile app development companies in new york #top mobile app development companies in usa #top 5 mobile app development companies

Derek  Champlin

Derek Champlin

1597209420

Oracle Coding Interview Questions

Daily coding problems

They are a wide variety of questions inspired by real programming interviews, with in-depth solutions that clearly take you through each core concept.

Get exceptionally good at coding interviews by solving one problem every day.

We will together solve these problems using JavaScript.

Problem #1

Question

We say a number is sparse if there are no adjacent ones in its binary representation.

For example, 21 (10101) is sparse, but 22 (10110) is not. For a given input N, find the smallest sparse number greater than or equal to N.

Do this in faster than O(N log N) time.

Solution

First of all, convert a integer to binary as follows.

Then we implement the following get_next_sparse(num) function that returns the smallest sparse number greater than or equal num.

We loop through an array of string and break when the current digit and previous digit are equal to the string of 1 and then create the array of zeros as follows.

#technology #interview #interview-questions #javascript #javascript-tips