No of questions: 60+

Kotlin Questions:

Q. Explain all scope function and its usecase ?
Ans -> https://www.youtube.com/watch?v=Vy-dS2SVoHk&ab_channel=PhilippLackner

Q. lazy vs lateinit

Q. High order functions
Ans -> https://www.youtube.com/watch?v=ZZuPgOhgQHc&ab_channel=SimplifiedCoding
https://proandroiddev.com/kotlin-pearls-lambdas-with-a-context-58f26ab2eb1d

Q. What is Trailing lamda

Q. Unit, Nothing, Any
Ans -> https://medium.com/proandroiddev/kotlin-pearls-7-unit-nothing-any-and-null-cbbbbca86c2d

Q. What is internal keyword use?
Ans -> Setting a declaration as internal means that it'll be available in the same module only.

Q. const, val, var, companion object and object (Use and difference)
Ans -> var - mutable variables
val - immutable variable assigned at runtime
const val - assigned at compile time
companion object - Inside this block we can define static variables/function inside classes/files.
object - Used to make singleton classes ( inside this class all functions and variables will be static )

Q. Use of open (Inheritence in kotlin vs java)

Q. passing vararg as parameter vs passing a list

Q. is, as, as?, in, out

Q. Extension vs inline vs inflix vs high order function there benefit in term of memory.

Q. operator keyword

Q. if(i != null) vs i?.let{}

Q. use of ::
Ans -> https://stackoverflow.com/questions/47400942/what-does-mean-in-kotlin

Q. Elvis operator

Q. Difference between volatile and syncronized.
Ans -> https://blog.knoldus.com/difference-between-synchronized-and-volatile-in-java/

Q. run{} vs runBlocking{}

Q. what is use of Anonymous classes? Example
Ans -> https://www.youtube.com/watch?v=1dKsPrEcUFY&ab_channel=PhilippLackner

Q. enum vs sealed class

Q. Normal nested class vs nested class with inner keyword
Ans -> https://www.youtube.com/watch?v=3bCqDGcfpP0&ab_channel=PRABEESHRK

Q. external, internal
Ans -> External: The external keyword in Kotlin is the same as the native keyword in Java. Both mean the implementation of the method comes from the native library.
Internal: The internal visibility modifier means that the member is visible within the same module.

Q. Questions based on lamda function in different situations.

Q. Interface vs abstract

Q. What is referential equality( === ) and structal equality( == )

Q. Questions based on coroutine scopes

Q. What is coroutines dispatchers there type and work.

Q. What is coroutines context.

Q. What is coroutines builder, its type and there work.

Q. Difference between Default and IO Dispatchers.

Q. async, await, awaitAll

Q. Flows vs live data, uses of flow when and when live data

Q. How to make singleton class in java?

Q. kotlin Deligation
Ans -> https://www.youtube.com/watch?v=MfJB-JhRAoQ&ab_channel=PhilippLackner

General Questions:

Q. SOLID Principles

Android Questions:

Q. Activity lifecycle when new activity (B) opened Ans -> onPause (A) -> onStart (B) -> onResume (B) -> onStop (A)

Q. Activity lifecycle when call comes or app goes to Bg?
Ans -> onPause and onStop. After call cut onRestart onStart onResume

Q. Which activity life cycle method trigger when orientation change?
Ans -> onPause() -> onSaveInstanceState() -> onStop() -> onDestroy() onCreate() -> onStart() -> onResume()

Q. Lets say we opened 3 activites (A,B,C) one after another and C is on top and A was the first activity. When we close activity C we want to send data to activity A. How can we do it in different ways.

Q. How recycler view works internally? Cons of recycler view.
Ans -> https://medium.com/1mgofficial/how-recyclerview-works-internally-71290de5d2c4

Q. Why Single activity app?
Ans -> https://oozou.com/blog/reasons-to-use-android-single-activity-architecture-with-navigation-component-36

Q. When onDestroy will get called before onPause or onStop?
Ans -> When their is an exception in onCreate/onPause/onResume nothing gets called and when we call finish() only onDestroy is called.

Q. To access gallery photo from our app we do not need any permission even though those photos are in external storage. Why?

Q. Types of URI
Ans -> Data, File, Content and Resource

Q. How room works internally

Q. What are interceptors

Q. In which project will you use data binding and in which viewBinding?

Q. Diff between MVVM and MVVM Clean

Q. Why MVVM, Difference between MVVM and other arch patterns

Q. Launch mode and there type and differences.
Ans -> https://medium.com/mindorks/android-launch-mode-787d28952959

Q. Lifetime of object class
Short Ans -> Till the app lives
Detailed Ans -> https://stackoverflow.com/questions/1944369/android-static-object-lifecycle/1944564#1944564

Q. Dagger Hilt @Singleton vs object class
Ans -> https://stackoverflow.com/questions/73449682/what-should-i-use-for-singleton-classes-a-real-singleton-or-singleton-annotati

Q. What is use of DI? Ans -> Manage scope of object easily, easy testing, managing dependencies easily

Q. Constraint layout groups
Ans -> https://stackoverflow.com/questions/42118674/how-to-group-multiple-views-in-a-constraintlayout

Q. Diff between virtual back button of android system and back button of toolbar inside the app.

Q. What are Intent Service

Q. What is pending intent

Q. How to inject interface
Ans -> https://write.agrevolution.in/dependency-injection-with-hilt-part-2-ee5fea58bab2

Q. DI Qualifiers
Ans -> https://blog.mindorks.com/dagger-hilt-tutorial

Q. Use of Application class

Q. Design and architecture patterns
Ans -> Design: https://blog.mindorks.com/mastering-design-patterns-in-android-with-kotlin

Q. Types of Services?

Q. Broadcast receiver

Q. What is use of channels in android

Q. How to start a service through Broadcast receiver and vice versa

Q. How viewModel works internally and retain data during configuration change (Even after actiivty destroys and recreate in config change viewModels maintain itself)

Q. Concept of viewModel factory

Q. Concept of shared view model and how to implement it.

Q. ViewModel vs AndroidViewModel

Q. Activities, fragment back stack

Q. Passing data from activities to fragment

Q. Types of intent which is used when

Q. How to communicate between service and activity

Q. What is job scheduler and its work.

Q. Memory leaks identification

Q. Major factors app performance depends upon

Q. Desgin Patterns
Ans -> https://blog.mindorks.com/mastering-design-patterns-in-android-with-kotlin/

Q. What is difference between using supportFragmentManager and nav component for navigation?

Q. How to clear all the activites in the backstack and open new

Q. Can a data class extend another data class?

Q. How to create a final class in kotlin?

Q. What is difference between instrumented and UI test

Q. Lifecycle of a view

Q. Difference between flow.emit(data) and flow.value = data

Scenario based questions

Q. Whats wrong in this code ?

companion object {
    val retrofit = Retrofit.Builder()
        .baseUrl(BASE_URL)
        .addConverterFactory(GsonConverterFactory.create())
        .build()
    const val BASE_URL = "https://api.openai.com/"
}

Q. I am using nav component in my app there are 5 activities in my app 1 is the home activity (containing 4 buttons) where I am currently on. When i click on button multiple times all 3 buttons work fine and redirect me to their respective activity. But the 4th button creates multiple instances of the activity (implementation to navigation is same for all 4 buttons) What could be the possible cause of this bug?

Q. You have an API which has some common keys for each endpoint in its response model. How will you design your data classes in that case?Explain different ways it can be done

Q. Do the field variables of ViewHolder class gets initiallized everytime onBind is called?

Q.

class Dum {
    
    private val x = 1
    init {
        val y = 2
    }
    private val z = 2

}

What will be the secquence in which x, y, z will be initiallized when the object of Dum class is created?