Class loading process and class initialization timing

Class loading process and class initialization timing

package reflection;

public class Test05 {
    
    
    static {
    
    
        System.out.println("Main初始化");
    }
    public static void main(String[] args) {
    
    
        //类加载过程
//        A a = new A();
//        System.out.println(A.m);
        /*
        1.加载到内存,生成类的Class对象
        2.连接:类的静态变量分配内存,赋初值 m=0
        3.类初始化 <clinit>(){
                System.out.println("类初始化");
                m=200;
                m=100
            }
            输出:类初始化
                初始化
                200
         */
        //测试类初始化时机
        //A a1 = new A();
        /*Main初始化
        父类初始化!
        A类初始化
        A类构造器初始化
         */
        //System.out.println(A.m);
        /*注意
        Main初始化
        父类初始化!
        A类初始化
        100
         */
        //System.out.println(A.f);//子类不初始化
        /*
        Main初始化
        父类初始化!
        2
         */
        System.out.println(A.M);//常量在连接阶段放到常量池中,父类子类均不初始化
        /*
        Main初始化
        200
         */
    }
}
class F{
    
    
    static {
    
    
        System.out.println("父类初始化!");
    }
    static int f = 2;
}
class A extends F{
    
    
    static {
    
    
        System.out.println("A类初始化");
        m=200;
    }
    static int m=100;
    static final int M=200;
    public A(){
    
    
        System.out.println("A类构造器初始化");//出现在对象初始化时
    }
}

process:
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Origin blog.csdn.net/qq_40976428/article/details/108651761