我们什么时候说java中加载了类？(When do we say class is loaded in java?)

 当我们说一个class被“加载”时，它意味着什么？ 
 
 例如，据说Static init块在类加载时执行。 什么时候加载了class ？ 
 
 请参阅Kathy Sierra的书中的代码： 
 
class Bird {
    {
        System.out.print("b1 ");
    }
    public Bird() {
        System.out.print("b2 ");
    }
}

class Raptor extends Bird {
    static {
        System.out.print("r1 ");
    }
    public Raptor() {
        System.out.print("r2 ");
    }
    {
        System.out.print("r3 ");
    }
    static {
        System.out.print("r4 ");
    }
}

class Hawk extends Raptor {
    public static void main(String[] args) {
        System.out.print("pre "); //1
        new Hawk();//2
        System.out.println("hawk ");
    }
}
 
 上面代码的输出是： r1 r4 pre b1 b2 r3 r2 hawk 
 
 我不能理解在r1之后打印prefor的结果。 哪部分代码加载了Raptor类？ 
 
 其中一个答案是： 
 
 “该类在最后一刻被初始化，但在访问其任何成员之前”。 
 
 但按照这个逻辑，不应该在r1之前预先打印？ 由于第2行在执行line1后访问类Raptor的构造函数。 

What does it mean when we say a class is "loaded"?
 
For example it is said that Static init blocks are executed at the time of class loading. When exactly class is loaded? 
 
Please see this code from Kathy Sierra's book:
 
class Bird {
    {
        System.out.print("b1 ");
    }
    public Bird() {
        System.out.print("b2 ");
    }
}

class Raptor extends Bird {
    static {
        System.out.print("r1 ");
    }
    public Raptor() {
        System.out.print("r2 ");
    }
    {
        System.out.print("r3 ");
    }
    static {
        System.out.print("r4 ");
    }
}

class Hawk extends Raptor {
    public static void main(String[] args) {
        System.out.print("pre "); //1
        new Hawk();//2
        System.out.println("hawk ");
    }
}
 
The output of above code is: r1 r4 pre b1 b2 r3 r2 hawk
 
I cant not understand howcome pre is printed after r1. Which part of the code loaded Raptor class?
 
One of the answer says :
 
"the class is initialized at the last possible moment, but before any of its members is accessed".
 
But by that logic, shouldn't pre be printed BEFORE r1? Since line 2 accesses constructor of class Raptor AFTER execution of line1.

原文：https://stackoverflow.com/questions/39412177