package FinalizeTest;public class Person {        public Person(){        System.out.println("person created");    }    @Override    protected void finalize() throws Throwable {        // TODO Auto-generated method stub        System.out.println("gc ");        throw new Exception("no effect");    }}package FinalizeTest;public class MainTest {    /**     * @param args     */    public static void main(String[] args) {        // TODO Auto-generated method stub        Person per = new Person();        per = null;        System.gc();        System.out.println("hello world");    }}輸出為person createdhello worldgc 代碼如上所示， 求解釋為什么hello world會在gc之前輸出？？