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Polymorphism is running behavior! The certificate is as follows: import java.util.Random; public class InterviewTest { public static Animal getInstance(int key) { switch(key) { case 0: //If key=0 return new Cat(); //Return to the newly created object (CAT) case 1: return new Dog(); default: return new Pig(); ...

🎈 Author: Linux ape 🎈 Introduction: CSDN blog expert 🏆， Huawei cloud sharing expert 🏆， C/C + +, interview, question brushing and algorithm. Please consult me, pay attention to me and chat privately if you have any questions! 🎈 Attention column: C/C + + interview customs collection   (high quality articles are constantly updated ...

Hello, I'm Dabin. Recently, I read a lot of experience in the interview. I took the time to summarize the common interview questions of Java Concurrent Programming and share them with you here~ First of all, let's share a github warehouse with more than 200 classic computer books, including C language, C + +, Java, Python, front end, data ...

container java containers fall into two categories The first category: Collection is called CollectionThe second category: Map Collection collection The first type of Collection is called Collection. Set means that no matter what the structure of your container is, you can throw one element into it one by one; Map The second c ...

28. Simple difficulty: passing rate 40% explain: What value should we return when need is an empty string? This is a good question in the interview. For this problem, we should return 0 when need is an empty string. This is consistent with the C language's str () and Java's indexOf() definitions. Question to charity: haystack and need are onl ...

preface Java thread pool is one of the foundations that must be mastered in interview and work. Using thread pool can better plan the CPU utilization of applications and improve the fluency of application operation. This article will explore the application and principle of thread pool in the future. Through this article, you will learn: 1 ...

⚽ Digression Yesterday, a little friend came to me and asked me a lot of questions. What can I do? After understanding, I found that I don't know much about the data structure. I don't know much about how to build linked lists and stacks. I suggest you look at the data structure and fill it up. Let's brush the questions slowly. As for how to ...

HashMap is almost a must in the interview. When you ask HashMap, it must be inseparable from the capacity expansion mechanism. If you don't say much, the liver is over. We know that the bottom layer of HashMap is realized by array + linked list. After JDK1.8, red black tree is introduced. This paper analyzes the HashMap after JDK1.8. First, ex ...

Start time: 20210919 agent Purchasing agent, intermediary, changing ip, merchant, etc Study abroad intermediary (agent): help this American school recruit students. The intermediary is the agent of the school, and the intermediary completes the enrollment function instead of the school. Agency features: Intermediaries and agents do the same ...

BigDecimal is a type provided by the java.math package that can be used for precise operations. For example, in scenarios such as amount representation and amount calculation, double, float and other types cannot be used, but BigDecimal with better accuracy support should be used, and many internal methods, such as addition, subtraction, mu ...