About static blocks of code in Java

A. Static code block

① Features: As the class is loaded and executed only once, no matter how many times the object instance is created, the static block of code in this class is only executed once when the class instance is first created or when the static method is called directly using the class name, and if the first time you call a static method using the class name, Static code blocks are executed before the corresponding method is executed. (This also means that when you create a class instance or call a static method using the class name, the class is loaded into memory). If it is Staticcode s=null, such a declaration statement, the class is not loaded into memory.

② function: Used to initialize a class (not an object)

Two. Static method: ① If you simply create an object that contains a class with a static method and do not call a static method, the static method will not execute, and the main method in the main class is executed after executing the static block of code in the main class ②;

Two. Building code blocks

① form:

{System.out.println ("I am Building code block"); }

② function: Used to initialize an object, that is, every time a new object is created, it is executed once, and the order of execution is before the constructor.

About static blocks of code in Java