Real interview experience at a famous Android development company

After working as an Android developer for a few years at various startups, I felt it was time to start exploring opportunities at larger companies.

At present, everyone in major domestic companies wants to get involved. After comprehensive consideration, I chose to invest in a foreign company . Fortunately, it didn’t take long for me to receive a call from an interviewer from a well-known foreign company. First, he asked me if I had a job. I didn't have time and needed to conduct a round of phone screening interviews. I said I still needed to sort it out, so I asked to postpone it for ten minutes.

The first round of interviews was conducted soon, and it was conducted through an online meeting. The interviewer could speak Chinese, but asked me to introduce myself in English. Since I was not proficient in English, I did not have much in-depth knowledge about the project. , and then the interviewer asked me some Android professional knowledge, mainly Java, Android UI and performance optimization , as well as some of my feelings when developing software from scratch to one, as well as the modules and tools used , and finally asked I talked about the idea of ​​​​a programming question , and then said that I was pretty good and would write code offline next time.

I was very happy, but the interview that followed was something I will never forget .

During the second interview, I went across provinces for an offline interview. There were two people interviewing me, one of whom was an "old acquaintance". He praised me from the beginning for my good foundation. It sounded like the other one should be I was the project manager, and I answered the previous professional questions very well, but I went in the wrong direction when coding. The other interviewer showed no patience. I really wanted to give up at the time, but I calmed down and used it. Another way to solve it is that after getting the affirmative answer, I immediately explained my thinking and how I adjusted it. This level was passed . This question is an average question, but it requires a change of thinking. It also reminded me and made me aware of my weak points.

So we made three appointments that day and told me it was a group meeting and asked me to be prepared.

Three sides were for four people. In the first round, we were asked to introduce our project situation in detail , and then we were asked to recruit two people, and we were asked to form a team by ourselves. The two people who passed in the end could be admitted.

This is something I didn't expect, but at this point, the chances are still relatively high.

After forming the team, we drew questions. The second round was to design an Android application alone . What I drew was a single screen for an application, which needed to be designed from an Android perspective. Then we talked about the Android components used. What architecture to follow, how to lay it out, but also why it is designed like this, what problems are encountered, how to solve them, etc. This is not enough. The third round is about the problems that their APP has encountered in the actual development in the past. Let us provide as many solutions as possible. This link can be discussed. I am still relatively experienced in this area and my performance is relatively outstanding. , the interviewer asked me to wait for the results at night, and I stayed here all afternoon.

This form was something I had never done before, but I still successfully entered the HR interview. For example, how to deal with the conflict between work and life, how to resolve the existing pressure, what are the plans for the next three years, how to evaluate yourself, how to solve conflicts in the division of labor in a project, and other issues .

The whole interview felt very formal and standardized. The moment I entered the company for the interview, I had a strong desire to join. Now that I have been here for half a year, I am very sure that I am in the right place.

Now I will share with you the latest interview questions from major companies in 2023 that I have compiled. I hope that everyone will have a successful career and advance step by step.

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Chapter 1 Java Aspects

(1) Basic part of Java

1. What is the difference between abstract class and interface?
2. Let’s talk about what the final, static, and synchronized keywords can modify respectively, and what they do after modification?
3. Please briefly describe the differences between String, StringBuffer and StringBuilder?
4. What are the differences and usage scenarios between "equals", "==", and "hashCode"?
5. What is the difference between deep copy and shallow copy in Java?
6. Talk about the difference between Error and Exception?
7. What is the reflection mechanism? What are the application scenarios of the reflection mechanism?
8. Talk about how to override the equals() method? Why rewrite hashCode()?
9. How many types of IO streams are there in Java? What are the differences between BIO, NIO and AIO?
10. Talk about your understanding of type erasure in Java generics, and talk about its limitations?
11. Why should String be designed to be immutable?
12. Tell me about your understanding of Java annotations?
13. Talk about the creation and recycling timing of Java member variables, local variables and static variables?
14. Please tell me how String.length() works in Java?

(2) Java collection

1. Talk about the differences between List, Set, and Map?
2. Talk about the difference between ArrayList and LinkedList?
3. Please tell me the difference between HashMap and HashTable
4. Let’s talk about the expansion mechanism of ArrayList?
5. How is HashMap implemented?
6. Please briefly describe the working principle and usage of LinkedHashMap?
7. Talk about your understanding of ConcurrentHashMap?

(3) Java multithreading

1. What are the ways to use multithreading in Java?
2. Tell me about the states of threads?
3. How to achieve synchronization in multiple threads?
4. Let’s talk about thread deadlock. How to effectively avoid thread deadlock?
5. Talk about the reasons for thread blocking?
6. Please talk about the difference between run() and start() in Thread?
7. What is the difference between synchronized and volatile keywords?
8. How to ensure thread safety?
9. Talk about the usage and principle of ThreadLocal?
10. What is the difference between notify and notifyAll in Java threads?
11. What is a thread pool? How to create a thread pool?
12. Let’s talk about the common locks in Java threads?
13. Let’s talk about the difference between thread sleep() and wait()?
14. What are pessimistic locking and optimistic locking?
15. What is BlockingQueue? Please analyze its internal principles and talk about its usage scenarios?
16. Let’s talk about what are the thread-safe collections in Java?
17. Why does the Atomic class appear in Java? Try to analyze its principles and shortcomings?
18. Talk about the usage scenarios of ThreadLocal? What features does it have compared to Synchronized?

(4) Java virtual machine

1. Let’s talk about JAVA garbage collection mechanism?
2. Answer: What are strong, soft, weak, and virtual references and the differences between them?
3. Briefly describe the loading mechanism and loading process of classes in JVM?
4. What are the principles and differences between JVM, Dalvik and ART?
5. Please talk about Java's memory recycling mechanism?
6. What is JMM? What problems does it have? How to solve it?

Chapter 2 Android

(1) Related to the four major components of Android

1. What are the common communication methods between Activity and Fragment?
2. Application scenarios of LaunchMode?
3. What is the difference between BroadcastReceiver and LocalBroadcastReceiver?
4. How much do you know about Context?
5. What is IntentFilter? What are the usage scenarios?
6. Let’s talk about the difference, life cycle and usage scenarios between startService and bindService?
7. How does Service keep alive?
8. Briefly introduce how ContentProvider realizes data sharing?
9. Talk about the life cycle of Activity when switching between horizontal and vertical screens?
10. What are the calling timings and usage scenarios of the onNewIntent method in Activity?
11. Is there a limit to the size of data transmitted by an Intent? How to solve?
12. Talk about the relationship between ContentProvider, ContentResolver and ContentObserver?
13. Talk about the Activity loading process?

(2) Android asynchronous tasks and message mechanism

1. What are the usage scenarios and usage of HandlerThread?
2. What are the application scenarios and usage postures of IntentService?
3. What are the advantages and disadvantages of AsyncTask?
4. Talk about your understanding of Activity.runOnUiThread?
5. Can child threads update UI? Why?
6. Let’s talk about the Handler mechanism and principles?
7. Why does creating a Handler in a child thread throw an exception?
8. Try to analyze the differences and application scenarios of Handler's post and sendMessage methods from the source code perspective?
9. There is an infinite loop in Handler. Why is it not blocking the main thread? What is the principle?

(3) Android UI drawing related

1. What is the difference between Android tweening animation and attribute animation?
2. What are Window and DecorView? How is DecorView connected to Window?
3. Briefly describe the refresh mechanism of UI in Android?
4. Which one of LinearLayout, FrameLayout and RelativeLayout is more efficient and why?
5. Let’s talk about Android’s event distribution mechanism?
6. Talk about the process of customizing View?
7. What optimizations have you done for RecyclerView?
8. Let’s talk about how to optimize ListView?
9. Talk about the process of customizing LayoutManager?
10. What are RemoteViews? What are the usage scenarios?
11. Let’s talk about several methods to obtain the width and height of View?
12. Let’s talk about interpolators and estimators?
13. What are the differences between getDimension, getDimensionPixelOffset and getDimensionPixelSize?
14. Please talk about the usage and application scenarios of StaticLayout in the source code?
15. Have you ever used ConstraintLayout? What are its characteristics?
16. Regarding LayoutInflater, how does it obtain the specific View through the inflate method?
17. Let’s talk about lazy loading of Fragment?
18. Talk about the caching mechanism of RecyclerView?
19. Please talk about the difference between View.inflate and LayoutInflater.inflate?
20. Please talk about the differences and application scenarios between invalidate() and postInvalidate() methods?
21. Let’s talk about custom View and custom ViewGroup?
22. Let’s talk about the usage scenarios and usage of SurfaceView and TextureView?
23. Let’s talk about the differences between the several refresh methods of RecyclerView.Adapter?
24. Talk about your understanding of Window and WindowManager?
25. Let’s talk about the relationship between Activity, View and Window?
26. Have you heard about WindowInsets? What are its applications?
27. What are the differences between several common displacement methods of View in Android?
28. Why is ViewPager nested ViewPager, and the inner ViewPager scrolling is not intercepted?
29. Please talk about the life cycle of Fragment?
30. Please talk about what is a synchronization barrier?
31. Let’s talk about how ViewDragHelper works?
32. Let’s talk about the screen refresh mechanism?

(4) Android performance tuning related

1. Tell us about your understanding of Android performance optimization?
2. What situations generally cause memory leaks?
3. How to effectively avoid memory leak problems when customizing Handler?
4. What situations will cause oom problems?
5. ANR occurrence scenarios and solutions?
6. Talk about memory optimization methods in Android?
7. Let’s talk about layout optimization techniques?
8. Image optimization solution in Android?
9. How to analyze and locate the Android Native Crash problem?
10. Let’s talk about how to slim down apk?
11. Talk about how you optimize the app startup process?
12. Talk about the steps of code obfuscation?
13. Let’s talk about how to optimize WebView?
14. How to handle loading of large images?
15. Let’s talk about how to optimize network requests?
16. Please talk about how to load Bitmap and prevent memory overflow?

(5) IPC in Android

1. Please answer the communication method between Android processes?
2. Please talk about your understanding of the Binder mechanism?
3. Talk about AIDL?

(6) Android system SDK related

1. Please briefly talk about the architectural composition of the Android system?
2. Are SharedPreferences thread-safe? What is the difference between its commit and apply methods?
3. What is the difference between Serializable and Parcelable?
4. Please briefly describe the new features of Android 7.0?
5. Talk about the difference between ArrayMap and HashMap?
6. Briefly talk about the principle of LruCache?
7. Why is it recommended to use SparseArray instead of HashMap?
8. What is the difference between PathClassLoader and DexClassLoader?
9. Talk about the difference between HttpClient and HttpUrlConnection? And talk about why the former will be replaced?
10. What is Lifecycle? Please analyze its internal principles and usage scenarios?
11. Let’s talk about Android’s signature mechanism?
12. Talk about the process of building Android apk?
13. Briefly describe what new features are added in Android 8.0 and 9.0?
14. Let’s talk about what content has been updated in Android 10? How to adapt it?
15. Please briefly describe the installation process of Apk?
16. How do Java and JS codes interact with each other? Have you done any relevant optimization?
17. What is JNI? Specifically, how to implement intermodulation between Java and C++?
18. Please briefly describe the startup process of the app starting from clicking the icon?

(7) Third-party framework analysis

1. Talk about the working principle of LeakCanray?
2. Let’s talk about the principle of EventBus?
3. Let’s talk about the interceptor (Interceptor) in network requests?
4. Let’s talk about Glide’s caching mechanism?
5. What problem does ViewModel appear to solve? And briefly talk about its internal principles?
6. Please talk about the implementation principle of the dependency injection framework ButterKnife?
7. Let’s talk about the back pressure principle of RxJava?

(8) Comprehensive technology

1. Please talk about your understanding of MVC and MVP?
2. Introduce the storage methods you know about Android?
3. Briefly describe the principle of thermal repair?
4. Talk about how to adapt to more models?
5. Please talk about how you implement multi-channel packaging?
6. How do you handle the Presenter layer in MVP to prevent memory leaks?
7. How to calculate the memory space occupied by an image?
8. Have you ever encountered a 64k problem and how to solve it?
9. How to optimize Gradle's build speed?
10. How to get Android device unique ID?
11. Let’s talk about the impact of disabling http in Android P on our development?
12. What is AOP? What are its application scenarios in Android?
13. What is MVVM? How do you apply this to specific projects?
14. Please talk about how you implement data burying?
15. If you were asked to implement the breakpoint upload function, how do you think you should do it?
16. What are the characteristics of images in webp and svg formats? How should it be used in Android?
17. Tell me how you do unit testing? And how to apply it in MVP and MVVM?
18. Do you have any ideas and suggestions for loading GIF images?
19. Why migrate your project to AndroidX? How to migrate?

(9) Data structure

1. What is bubble sort? How to optimize?
2. Please use Java to implement a simple singly linked list?
3. How to reverse a singly linked list?
4. Talk about your understanding of time complexity and space complexity?
5. Let’s talk about how to judge whether a linked list is a ring?
6. What is a red-black tree? Why use red-black trees?
7. What is quick sort? How to optimize?
8. Talk about circular queue?
9. How to determine singly linked list intersection

(10) Design pattern

1. Please briefly talk about the singleton pattern?
2. How much do you know about the six basic principles of object-oriented?
3. Please list several common factory patterns and explain their usage?
4. Tell us about the design patterns and usage scenarios used in the project?
5. What is proxy mode? how to use? Proxy mode in Android source code?
6. Let’s talk about the usage scenarios of singleton mode, builder mode and factory mode? How to choose reasonably?
7. Talk about your understanding of the prototype pattern?
8. Please talk about the principles of the strategy pattern and its application scenarios?
9. What is the difference between static proxy and dynamic proxy? In what scenarios are they used?
10. Let’s talk about the usage scenarios of the responsibility chain model?

(11) Computer network aspects

1. Please briefly describe the difference between HTTP and HTTPS?
2. Talk about the difference between https, udp and socket?
3. Please briefly describe the process of an http network request?
4. Let’s talk about the TCP/IP three-way handshake and four-way wave?
5. Why is HTTP a reliable data transfer protocol?
6. What are the layers of the TCP/IP protocol? Which layer do TCP and HTTP belong to?

(12) Kotlin aspect

1. Please briefly describe what is Kotlin? What properties does it have?
2. What is the role of the @JvmOverloads annotation in Kotlin?
3. What is the difference between List and MutableList in Kotlin?
4. What are some common ways to implement singletons in Kotlin?
5. Talk about your understanding of the data keyword in Kotlin? What are the characteristics compared to the ordinary category?
6. What are delegate properties? Please briefly talk about its usage scenarios and principles?
7. Please give an example of the application scenarios and differences between the with and apply functions in Kotlin?
8. What is the role of Unit type in Kotlin and its difference from Void in Java?
9. What are the principles and usage scenarios of the infix keyword in Kotlin?
10. What are the visibility modifiers in Kotlin? What is the difference compared to Java?
11. What issues do you think need to be paid attention to when developing mixed Kotlin and Java?
12. What is deconstruction in Kotlin? How to use it?
13. In Kotlin, what are inline functions? what's the effect?
14. Talk about the construction method in kotlin? What precautions?
15. Let’s talk about Sequence in Kotlin. Why is it more efficient in processing collection operations?
16. Please talk about Coroutines in Kotlin, how is it different from threads? What are the advantages?
17. How to safely handle nullable types in Kotlin?
18. Talk about the similarities and differences between Any in Kotlin and Object in Java?
19. Are there implicit conversions of data types in Kotlin? Why?
20. What are the ways to traverse collections in Kotlin?