Exception in thread "Timer-0" java.lang.IllegalArgumentException: bound must be positive
at java.util.Random.nextInt(Random.java:388)
at com.tarena.fly.Bee.(Bee.java:14)
at com.tarena.fly.ShootGame.nextOne(ShootGame.java:348)
at com.tarena.fly.ShootGame.enterAction(ShootGame.java:207)
at com.tarena.fly.ShootGame$2.run(ShootGame.java:189)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)
这个是什么意思