运行下面代码，输出的结果是
class A {
public A() {
System.out.println("class A");
}
{
System.out.println("I'm A class"); }
static {
System.out.println("class A static"); }
}
public class B extends A {
public B() {
System.out.println("class B");
}
{
System.out.println("I'm B class"); }
static {
System.out.println("class B static"); }
public static
void main(String[] args) {
new B();
} 