Byte Summer Internship - 20220304

problem

1. Self introduction. . Choose a familiar project in your resume to talk about .

• Let's talk about the implementation of login authentication
• JWT、token、session What's the difference
• Is the library table designed by yourself
• The logic of payment. Let's talk about the process , Or find a familiar module to talk about （ The business layer ）

2. Know what linux Common commands ？ Project deployment what container the project is in ？

3. What have you met JVM problem , And check it out ？

4. Understand what singleton mode is ？ Write code to implement a single example mode ？

answer ：

• Code

public class Main {
    
    public static void main(String[] args){
    
        // test  instance1 It's created directly ,instance2 Is created before returning 
        Singleton instance1 = Singleton.getInstance();
        Singleton instance2 = Singleton.getInstance();
        System.out.println(instance1==instance2);
    }
}
class Singleton{
    
    // Use the member variable of a class to mark whether the class has created an instance 
    private static Singleton instance;
    // Privatization has no parameters 
    private Singleton(){
    }
    // Provide external interface , Static class methods , When the class is loaded, call , It can be called directly through the class name 
    // Because to access the privatized parameterless structure , So add static modification 
    public static Singleton getInstance(){
    
        if(instance==null)instance=new Singleton();
        return instance;
    }
}

5. Where do you usually learn technology , Have you learned any new technology recently ？

6. Do you have any questions or additions ？