What are the uses of static?

Everyone knows static The two basic uses of keyword : Static variables and static methods . It means being static Variable decorated / Method

All belong to static resources of class , Shared by class instance .

In addition to static variables and static methods ,static Also used for static blocks , Used for initialization operations :

Besides static Also used to decorate internal classes , This is called a static inner class .

The last use is static packet guidance , namely import static .import static Is in JDK 1.5 New features introduced later , Can be used to refer to

To import static resources in a class , And you don't need to use the class name , You can use the resource name directly , such as :

public calss PreCache{

static{

// Carry out relevant operations

}

}

import static java.lang.Math.*;

public class Test{

public static void main(String[] args){

//System.out.println(Math.sin(20)); Traditional practice

System.out.println(sin(20));

}

}