Android Interview Questions

Android Interview Questions - Your Cheat Sheet For Android Interview

We will be adding answers to the more questions on our Mindorks website.

Contents

• Data Structures And Algorithms
• Core Java
• Core Android
• Arctitecture
• Design Problem
• Tools And Technologies
• Android Test Driven Development
• Others

Data Structures And Algorithms

The level of questions asked on Data Structures And Algorithms totally depends on the company for which you are applying.

• Array
• LinkedList
• DoublyLinkedList
• Stack
• Queue
• PriorityQueue
• Dynamic Programming
• String Manipulation
• Binary Tree
• Binary Search Tree
• Sorting Algorithms
• Hash Table or Hash Map
• Breadth First Search
• Depth First Search
• Greedy Algorithm

Core Java

• Explain OOP Concept.
• Differences between abstract classes and interfaces?
• What is serialization? How do you implement it?
• What is Singleton class?
• What is anonymous classes?
• What is the difference between using == and .equals on a string?
• What is the hashCode() and equals() used for?
• What are these final, finally and finalize?
• What is memory leak and how does Java handle it?
• What is garbage collector? How it works?
• Arrays vs ArrayLists.
• HashSet vs TreeSet.
• Typecast in Java.
• Difference between method overloading and overriding.
• What are the access modifiers you know? What does each one do?
• Can an Interface extend another Interface?
• What does the static word mean in Java?
• Can a static method be overridden in Java?
• What is Polymorphism? What about Inheritance?
• What is the difference between an Integer and int?
• Do objects get passed by reference or value in Java? Elaborate on that.
• What is a ThreadPoolExecutor? Link
• What the difference between local, instance and class variables?
• What is reflection?
• What are strong, soft and weak references in Java?
• What is dependency injection? Can you name few libraries? Have you used any?
• What does the keyword synchronized mean?
• What does it means to say that a String is immutable?
• What are transient and volatile modifiers?
• What is the finalize() method?
• How does the try{}finally{} works?
• What is the difference between instantiation and initialization of an object?
• When is a static block run?
• Explain Generics in Java?
• Difference between StringBuffer and StringBuilder?
• How is a StringBuilder implemented to avoid the immutable string allocation problem?
• What is Autoboxing and Unboxing?
• What’s the difference between an Enumeration and an Iterator?
• What is the difference between fail-fast and fail safe in Java?
• What is Java priority queue?
• What are the design patterns? Link

Core Android

• Explain activity lifecycle.
• Tell all the Android appplication components.
• Service vs IntentService.
• What is the structure of an Android Application?
• How to persist data in an Android app?
• How would you perform a long-running operation in an application?
• How would you communicate between two Fragments?
• Explain Android notification system?
• How can two distinct Android apps interact?
• What is Fragment?
• Explain the lifecycle of a Fragment.
• What is Dialog in Android?
• What is View in Android?
• Can you create custom views? How?
• What are ViewGroups and how they are different from the views?
• What is the difference between a fragment and an activity? Explain the relationship between the two.
• What is the difference between Serializable and Parcelable? Which is the best approach in Android?
• What are "launch modes"? Link
• What are Intents?
• What is an Implicit Intent?
• What is an Explicit Intent?
• What is an AsyncTask?
• What is a BroadcastReceiver?
• What is DDMS and what can you do with it?
• What is the support library? Why was it introduced?
• What is a ContentProvider and what is it typically used for?
• What is ADB?
• What is ANR? How can the ANR be prevented?
• What is AndroidManifest.xml?
• Describe how broadcasts and intents work to be able to pass messages around your app?
• How do you handle Bitmaps in Android as it takes too much memory?
• What are different ways to store data in your Android app?
• What is the Dalvik Virtual Machine?
• What is the relationship between the life cycle of an AsyncTask and an Activity? What problems can this result in? How can these problems be avoided?
• What is the function of an intent filter?
• What is a Sticky Intent?
• What is AIDL? Enumerate the steps in creating a bounded service through AIDL.
• What are the different protection levels in permission?
• How would you preserve Activity state during a screen rotation?
• Relative Layout vs Linear Layout.
• How to implement XML namespaces?
• Difference between View.GONE and View.INVISIBLE?
• What is the difference between a regular bitmap and a nine-patch image?
• Tell about the bitmap pool. Link
• How to avoid memory leaks in Android?
• What are widgets on Home-Screen in Android?
• What is AAPT?
• How do you find memory leaks in Android applications?
• How do you troubleshoot a crashing application?
• Why should you avoid to run non-ui code on the main thread?
• How did you support different types of resolutions?
• What is Doze? What about App Standby?
• What can you use for background processing in Android?
• What is ORM? How does it work?
• What is a Loader?
• What is the NDK and why is it useful?
• What is the StrictMode? Link
• What is Lint? What is it used for?
• What is a SurfaceView?
• What is the difference between ListView and RecyclerView?
• What is the ViewHolder pattern? Why should we use it?
• What is a PendingIntent?
• Can you manually call the Garbage collector?
• What is the best way to update the screen periodically?
• What are the different types of Broadcasts?
• Have you developed widgets? Describe. Link
• What is Context? How is it used? Link
• Do you know what is the view tree? How can you optimize its depth?
• What is the onTrimMemory method?
• Is it possible to run an Android app in multiple processes? How?
• How does the OutOfMemory happens?
• What is a spannable?
• What is renderscript? Link
• What are the differences between Dalvik and ART?
• FlatBuffers vs JSON. Link
• What are Annotations? Link, Link
• Tell about Constraint Layout Link
• HashMap, ArrayMap and SparseArray Link
• Explain Looper, Handler and HandlerThread. Link
• How to reduce battery usage in an android application? Link
• What is SnapHelper? Link

Arctitecture

• Describe the architecture of your last app.
• Describe MVP. Link
• What is presenter?
• What is model?
• Describe MVC.
• What is controller?
• Describe MVVM. Link
• Tell something about clean code Link

Design Problem

• Design Uber App.
• Design Facebook App.
• Design Facebook Near-By Friends App.
• Design WhatsApp.
• Design SnapChat.
• Design problems based on location based app.

Tools And Technologies

• Git. Link
• RxJava. Link
• Dagger 2. Link
• Android Development Useful Tools. Link

Android Test Driven Development

• What is Espresso? Link
• What is Robolectric? Link
• What is UI-Automator? Link
• Explain unit test.
• Explain instrumented test.
• Have you done unit testing or automatic testing?
• Why Mockito is used? [Link] (http://site.mockito.org/)
• Describe JUnit test.

Others

• Describe how REST APIs work.
• Describe SQLite.
• Describe database.
• Project Management tool - trello, basecamp, kanban, jira, asana.
• About build System - gradle, ant, buck.
• Reverse Engineering an APK.
• What is proguard used for?
• What is obfuscation? What is it used for? What about minification?
• How do you build your apps for release?
• APK Size Reduction. Link
• Android Development Best Practices. Link
• Android Code Style And Guidelines. Link
• Have you tried Kotlin? Link
• What are the metrics that you should measure continuously while android application development? Link

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