I have been recruiting Android programmers for the company recently, and I have been recruiting Android programmers for the company. Since I worked as a TeamLeader in 2015, I have habitually collected Android technical problems I usually encounter or interview questions seen by friends around me. After continuous screening, I finally condensed into a set of practical small question banks. (For all the questions in the question bank, please see below, it’s time to test your level.)
On the one hand, it is for the company's recruitment, and on the other hand, I want to use it to dig out my technical blind spots in the Android technology stack, and then repair and improve it, so as to improve my technical level.
I have been involved in programming since 2009, and until now I still feel that there is a lot to learn, and the learning process has also brought me a lot of sense of accomplishment, which drives me to learn more technical knowledge.
The 200+ questions I summarized are almost all "required questions". If you can understand them, you will be sure if you go to the interview. At the beginning, I wondered if doing this was suspected of helping others "cheating". Finally, I figured it out, this is something worth doing.
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First: It is a great thing for more people to learn more knowledge.
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Second: This is just a high degree of refinement of experience, so that those who have mastered the technology but don't know how to express themselves can learn how to present themselves in the interview.
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Third: If you just memorize these interview questions by rote, as long as the interviewer asks more in-depth questions, you can have an accurate understanding of this person, and the previously mentioned "helping people cheat" will no longer exist.
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Fourth: There are many ways to learn, but only good scholars will learn from the pool. If it is someone who does not want to learn, no matter how much and best information is provided in front of them, they will turn a blind eye.
Take our Android question as an example. If you can remember most of the answers, first, you are smart and have a good memory;
So if you are an interviewer and you happen to see this again, if conditions permit, please give more opportunities to such smart young people who are willing to learn.
Having said so much, going straight to the point, our interview questions include thirteen modules: data structure and algorithm, Java foundation, in-depth generics and annotations, concurrent programming, virtual machine principles, reflection classes, network programming, Kotlin, advanced UI, Framework kernel source code, component kernel, performance optimization, and open source framework . As shown below:
Perhaps for beginners, there is no need to look at the knowledge of the framework and Framework modules behind. Readers and friends can choose the corresponding modules to read according to their own situation.
Suitable for reading crowd
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Beginner/intermediate/advanced Android programmers who need interviews
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Those who want to fill in gaps
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People who want to continuously improve and expand their Android technology stack
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Android interviewer
Weixin directly scans the QR code to obtain
specific interview questions
Chapter 1 Algorithms and Data Structures Interview Questions
- Please talk about the principle of HashMap and SparseArrary, the advantages of SparseArrary compared to HashMap, how does ConcurrentHashMap achieve thread safety?
- Please talk about the principle of HashMap, the access process, why red-black tree is used, the comparison between red-black tree and complete binary tree, HashTab, concurrentHashMap, what is in the concurrent package?
- Please talk about the underlying principle of hashmap put(). When a conflict occurs, how to add it (traverse along the linked list, and compare the key values one by one to see if they are consistent. If they are consistent, overwrite and replace them. After the inconsistent traversal, insert the position)?
- Please tell me how ArrayList ensures thread safety, except for adding keywords?
- Please talk about ArrayList, HashMap, LinkedHashMap?
- Please talk about the implementation principle of HashMap, the conditions for expansion, and what are the conditions for converting a linked list to a red-black tree?
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Chapter 2 Java Core Basic Interview Questions
- Java provides abstract classes and interfaces, how to choose during development?
- What do overloading and overriding mean and what is the difference?
- What are static inner classes? What is the difference between non-static inner classes and non-static inner classes?
- When passing parameters in Java, is it passed by value or by reference?
- Difference between using equals and == for comparison
- String s = new String("xxx"); How many String objects are created?
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Chapter 3 Java In-depth Generics and Annotations Interview Questions
- What is generics, and what about generic erasure?
- Can List<String> be converted to List<Object>
- What is the difference between super and extends in Java generics?
- What are annotations? What are the usage scenarios?
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Chapter 4 Java Concurrent Programming Interview Questions
- If there is only one cpu, single core, is multi-threading still useful?
- What is the difference between sychronied modified ordinary methods and static methods? What is visibility?
- What optimizations did Synchronized do after JDK1.6
- The principle of CAS lock-free programming
- Principle of AQS
- Implementation principle of ReentrantLock
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Chapter 10 Framework Kernel Analysis Interview Questions
- What are the ways of multi-process communication in Android?
- Describe the principle of the Binder mechanism?
- Why does Android adopt Binder as the IPC mechanism?
- What is the working process of the Binder thread pool?
- What is the full name of AIDL? how to work? What types of data can be processed?
- The difference and connection between Pid&Uid in Android
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Chapter 11 Android Component Kernel Interview Questions
- The life cycle of Acitvity, how to destroy an Activity?
- Activity's 4 major startup modes, and issues that need attention in development, such as the call of onNewIntent()
- Intent display jump and implicit jump, how to use?
- Activity A jumps to B, B jumps to C, A cannot jump directly to C, how does A send a message to C?
- How does Activity save state?
- Please describe the startup process of the Activity, starting from clicking the icon.
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Chapter 12 Program Performance Optimization and Data Persistence Interview Questions
- The size of a picture 100x100 in memory?
- Memory optimization, memory thrashing and memory leaks.
- When does a memory leak happen? give a few examples
- Bitmap compression, the difference between 100% and 90% quality?
- Use of TraceView to find CPU usage
- Finding memory leaks
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Chapter 13 Open Source Framework Interview Questions
- The significance of componentization in the project
- The principle of ARouter in componentization
- Talk about your understanding of APT technology
- Talk about the caching mechanism design of the Glide framework
- Talk about your understanding of the Glide life cycle
- What should be the reason for memory overflow when using the Glide framework in the project?
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