Android developer - Interview questions

Hello, recently I made a job switch and have attended interviews in various companies. I would like to share the list of questions and topics I came across during the process.

Programming Basics

1. what is the difference between final, finally and finalize?Answer
2. Explain abstraction in OOPS concept
3. Explain inheritance in OOPS concept
4. How to achieve polymorphism and it's types?
5. What is Interface in Java?
6. Can we create Object for abstract class? No, we can't create. Explanation
7. Can we pass null value into HashMap?Answer
8. Different types of Exceptions.
9. Difference between array and arrayList. Answer
10. Difference between serializable and parcelable. Answer

Android questions

1. How to add multiple fragments in single activity? Answer
2. Difference types of services in android?
3. How to create a custom view and custom widget in android? Custom View, Custom widget
4. How to update a single item in recyclerView? Answer
5. Scope functions in Kotlin. Docs
6. Different types of Launch modes in android. Answer
7. How to check whether the lateinit variable is initialized? Answer
8. What is Elvis operator in kotlin? Answer
9. What is MultiDex in android? Explanation
10. Explain LiveData and it's types in android. Explanation
11. Difference between App bundle and APK. Answer
12. What is key store file in android? Explanation
13. Why we need to sign our app before releasing to PlayStore? Explanation
14. What is the use of Gradle in android? Answer
15. Explain build flavors in android. Answer
16. How to implement Dynamic module delivery? Docs
17. Coroutines in android. Docs
18. Broadcast receivers in android. Docs
19. Content providers in android. Docs
20. What is Intent and it's types? Blog
21. Activity and fragment lifecycle. Check this lifecycle cheat sheet
22. What is Job scheduler in android? Answer
23. Explain Alarm manager. Answer.
24. How does MVVM works. Answer
25. What is companion object in kotlin? Answer
26. Difference between val and const in kotlin. Answer
27. How room works internally? Answer
28. Explain Hilt in android. Answer

Additional resources
Kotlin cheat sheet 1
Kotlin cheat sheet and quick reference
Android cheat sheet

Please do share any interview topics and questions you came across in comments.
Hope this helps :-).

Comments

[Eric Donovan]

Just in case there are newbies reading this list and getting stressed. I've been developing native android apps professionally as a contractor for over 10 years, I think I'm quite a good developer, and quite a few of these I would have to look up, or are about android components that I haven't needed to use for years.

I can testify that, they are indeed the type of questions that are often asked in interviews though. They ask these questions because they don't know how else to identify good developers (no one really knows how to do that)

Some of these questions are just because the interviewer learnt something last week, and they are proud of it, so they decide to ask you about it in the interview "how does room work internally?" 😂

I have no idea if you can pass null into a java HashMap, it's doesn't sound like a very good idea. But just type HashMap into your IDE and click it, the docs or the source will tell you 🤷

Anyway good to know what you're getting into when you head for your Android interview.

If they happen to ask you all the specific questions you didn't look up before the interview, and don't make an offer, don't take it personally. Those kinds of interviews are just chance.

[Khondakar Afridi]

This was really helpful. Thanks mate!

[Geoffrey Erastus]

🤝

[Vincent Tsen]

Awesome!

[pam412]

Very Helpful!

[Godfirst Onuoha]

Nice

[Deepak]

Thanks a lot... Very helpful