定义如下程序:
public class Person{ { System.out.println("P1"); } static{ System.out.println("P2"); } public Person(){ System.out.println("P3"); } } public class Students extends Person{ static{ System.out.println("S1"); } { System.out.println("S2"); } public Students(){ System.out.println("S3") } public static void main(String[] args){ new Students(); } }程序执行结果是?()