Java构造函数的调用顺序

Question

鉴于以下代码，输出为：

A's 1
A's 2
B's 5

我无法理解订单是什么......

class A
{
    A(int number)
    {
        System.out.println("A's" + " "+ number);
    }
}

class B
{
    A aObject = new A(1);
    B(int number)
    {
        System.out.println("B's" + " "+ number);        
    }
    A aObject2 = new A(2);
}

public class myFirstProject {   
    public static void main(String[] args) {
        B bObj = new B(5);
    }
}