볼 게임, 다중 수신 거부




File list:
Balls
....\.classpath
....\.project
....\Ball$1.class
....\Ball.class
....\Ball.java
....\BouncingBalls.class
....\BouncingBalls.java
....\Buttons$ButtonHandler.class
....\Buttons.class
....\Buttons.java
....\JumpAreaPanel$1.class
....\JumpAreaPanel$2.class
....\JumpAreaPanel.class
....\JumpAreaPanel.java