public class PassiveUse { public static void main(String[] args) { System.out.println(NewBaby.hoursOfSleep); System.out.println(NewBaby.greeting); } static { System.out.println("PassiveUse is initialized"); } } class NewParent { static int hoursOfSleep = (int) (Math.random() * 3.0); static { System.out.println("NewParent is initialized"); } } class NewBaby extends NewParent { static final String greeting = "hello world"; static int hoursOfCry = (int) (Math.random() * 2.0); static { System.out.println("NewBaby is initialized"); } }
输出为:
PassiveUse is initialized
NewParent is initialized
2
hello world