Detailed explanation of the loading order of static methods

The difference between static code blocks and static methods in Java. Generally, if some code must be executed when the project starts, you need to use static code blocks. This kind of code is actively executed; it needs to be initialized when the project starts. , without creating an object, when other programs call it, you need to use static methods. This kind of code is passively executed. Static methods are already loaded when the class is loaded and can be called directly with the class name. For example, the main method must It is static. This is the program entry. The difference between the two is: the static code block is automatically executed; the static method is only executed when it is called. Static method

(1) In Java, you can define a method that does not require creating an object. This method is a static method. To achieve this effect, you only need to add the static keyword before the method defined in the class. For example: public static int maximum(int n1,int n2) When using static methods of a class, please note: In a static method, a can only directly call other static members (including variables and methods) of the same class, but cannot directly access non-static members in the class. This is because non-static methods and variables need to create an instance object of the class before they can be used, while static methods do not need to create any objects before use. b Static methods cannot reference the this and super keywords in any way, because static methods do not need to create any instance objects before use. When the static method is called, the object referenced by this is not generated at all.

(2) Static variables are variables that belong to the entire class rather than to an object. Note that variables within any method body cannot be declared static, for example: fun() { static int i=0;//Illegal. } (3) A class can use a static code block that is not included in any method body. When the class is loaded, the static code block is executed and only executed once. Static blocks are often used to initialize class attributes. For example: static { }

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public abstract class ClassLoadingTest {

    public static void main(String[] args) {
        User user3 = new User();
        
    }
}

   User user=  User("wang",18  "调用userSay静态方法""进入静态构造代码块"=  User("wang2333", 19"进入代码块"  User(String name, .name =.age = .name =   setAge(.age = .getName() + "调用say方法"

执行结果：
进入代码块
调用userSay静态方法
wang调用say方法
进入静态构造代码块
进入代码块
wang2333调用say方法
wang调用say方法
进入代码块

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