构造函数经典面试题

package text;


public class test extends B{
test(){
System.out.print("t");
A s = new B();
}
public static void main(String[] args) {
test t = new test();
}
}
class A{
A(){
System.out.print("AA");
}
}
class B extends A{
B(){
System.out.print("b");
A a = new A();
}
}


输出：AAbAAtAAbAA
原则：子类创建的时候先创建父类