Preface
This is a book that explains the core knowledge of java in the name of an interview. A lot of knowledge is what you usually use, but you may have overlooked many details. For example, the disturbance function of HashMap makes the hashing more uniform. In addition to this kind of hashing, ThreadLocal can also use the Fibonacci golden section hash, etc. A series of knowledge points are presented in this book through practice. You explain in depth.
If you can keep reading and follow the practical examples in the book to add code learning, then-there will be very profound gains.
If you understand, you really understand
It is the core purpose of this book to let you understand. For every knowledge point that requires in-depth understanding, analyze from the most basic principles.
Then learn these core knowledge points through examples that can be verified in practice, so that the learning content can be simple, but also more in-depth.
Forward + follow, and then add VX (tkzl6666) to get the free way to receive this "Java Handbook".
Chapter 1 What do the interviewers ask me
In this article, I will start from the perspective of a resume and briefly outline the abilities that R&D personnel should have. On the basis of this article, I will gradually expand the series of interview scenarios in the future, as well as detailed explanations of the corresponding interview questions and where to learn these knowledge Of a guide.
- -Programmer's wishes (your wishes?)
- 2. Xie Jifei's resume (resume template!)
- 3. Interview framework (questions I was asked during the interview)
- 4. Summary (summary of the whole chapter)
Chapter 2 Know your own technology stack blind spot
There is a commonly heard saying: The more you know, the more you don’t know. This is summarized by people who are actively learning. On the contrary, there is another sentence: The less you know, the less you don't know.
- —、Technology Stack Collection Questionnaire
- 2. Summary technical framework window
- Three, summary
Chapter 3 Why HashCode uses 31 as a multiplier
This article mainly explains the Hashcode related to the hash table. I originally wanted to talk about HashMap first, but as I sorted out the data, it was found that the hash of Hashcode occupies a very important design idea, so it is best to take this part of knowledge Complete, and then explain.
- 1. Interview questions
- 2. Resource download
- Three, source code explanation
- Four, summary
Chapter 4 HashMap disturbance function, load factor, expansion linked list split
Thanks to the master Doug Lea, HashMap has become the most frequently used and interviewed API. There is no way to design it too well!
- 1. Resource download
- Two, source code analysis
- Three, summary
Chapter 5 HashMap insertion, search, deletion, traversal, source code analysis
1. Data insertion process and source code analysis, 2. Linked list tree and tree to linked list, 3. The core knowledge of disordered set in the traversal process
Chapter 6 2-3 Balance Tree "Red-Black Tree Predecessor"
This chapter is combined with the extension of HashMap. In ldk1.8, HashMap is implemented using bucket array + linked list and red-black tree, so after explaining the core principles and API functions of the previous chapter, this chapter originally thought Go directly to the red-black tree, but if you want to understand the red-black tree, you need to understand its ins and outs, which is its predecessor, the 2-3 tree.
- 1. Interview questions
- 2. What is a 2-3 tree
- Three, 2-3 tree use
- Four, summary
Forward + follow, and then add VX (tkzl6666) to get the free way to receive this "Java Handbook".
Chapter 7 Principles of Red-Black Trees, Coloring, Rotation, and Relationship with 2-3 Trees
The structure and design of the red-black tree are excellent, and it also has complex processing logic in its implementation, including operations such as inserting or deleting nodes, color changes, and rotation operations. But if you just memorize these knowledge points, when to dye and when to rotate, it doesn't make much sense, and it will be forgotten after a long time. Therefore, it is more important to understand this part of the study.
- 1. Face j test questions
- 2. The equivalence of 2-3 trees and red-black trees
- Three, red and black trees
- Four, summary
Chapter 8 ArrayList core knowledge points
Speaking of data structures basically include; arrays, linked lists, queues, red-black trees, etc., but when you see these data structures and think of your usual development, it seems that you have not used them. So why study data structure? In fact, you are not using these knowledge points, but the API in Java has encapsulated each data structure into corresponding tool classes
- 1. Interview questions
- Second, the data structure
- Three, source code analysis
- Four, summary
Chapter 9 LinkedList insertion speed is not necessarily faster than ArrayList!
Data structure, algorithm logic, and source code skills can all empower your business development, and it is also the foundation for writing better and easier to extend programs, so it is very necessary to learn this knowledge.
- 1. Interview questions
- Second, the data structure
- Three, source code analysis
- Four, summary
Chapter 10 explains deque, delay queue, and blocking queue
Next, I will introduce the remaining stacks and queues in this chapter. In fact, this part of knowledge is not difficult. With the above understanding of arrays and linked lists, other data structures are basically extended from these two aspects.
- 1. Face j test questions
- Second, the data structure
- Three, source code learning
- Four, summary
Chapter 11 Collectios toolkit learning, sorting, dichotomy, shuffling, rotating
Next, we will learn about the algorithm tool classes provided in Java, collections
- 1. Face j questions
- Two, Collections tools
- Three, summary
Chapter 12 Is StringBuilder faster than String?
I can’t use it for my question development, why do you ask? Maybe this is the experience of most programmers when they apply for a job, and it is even annoying and irritating for everyone. Obviously, the money is given to screw the screws, what is clearly done is to write CRUD, and the person who is clearly responsible is the tool!
Obviously... there are many, but the company will not hire 5 years of development to do things with 3 years of experience, and obviously the company prefers R&D with added value. It's hard to say for some small companies, but in some large Internet companies, we all hope to recruit people with training value, and we prefer those who can quickly fight monsters and upgrades, and we are more willing to let such people take on greater responsibilities.
- 1. Interview questions
- 2. Is StringBuilder faster than String?
- Three, String source code analysis
- Four, StringBuilder source code analysis
- Five, StringBuffer source code analysis
- Six, commonly used API
- Seven, summary
Chapter 13 ThreadLocal
- —, interview questions
- Two, ThreadLocal analysis
- Three, summary
It is often said that the interview is making rockets and the entry is screwing. But do you really have the ability to build rockets? Most of them are self-deprecating who dare not admit their knowledge blind spots, technical bottlenecks, and lack of experience.
Therefore, it was never CRUD who chose you, nor did it make screws to make you a tool person. It is your technical ability that determines your horizons, which in turn determines the code you write!
At last
Precipitate, share, grow, so that you and others can gain something!