面试题 - 类继承的加载顺序

题目：请给出下面程序的打印结果

public class ClassFieldInParent {
    public ClassFieldInParent() {
        System.out.println("ClassFieldInParent");
    }
}

public class ClassParent {
    public ClassFieldInParent cfip = new ClassFieldInParent();
    public ClassParent() {
        System.out.println("ClassParent");
    }
}

public class ClassField {
    public ClassField() {
        System.out.println("ClassField");
    }
}

public class ClassSelf extends ClassParent {
    public ClassField c = new ClassField();
    public ClassSelf(){
        System.out.println("ClassSelf");
    }
    
    public static void main(String[] args){
        new ClassSelf();
    }
}

答案：

ClassFieldInParent
ClassParent
ClassField
ClassSelf

结论为：子类调用new方法时，父类首先被创建；执行父类构建子前先初始化父类的内部变量。

语句执行顺序为：父类成员变量->父类构建子->子类成员变量->子类构建子