fix:
Error in ClientHandler: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
	at java.util.ArrayList.rangeCheck(ArrayList.java:638)
	at java.util.ArrayList.get(ArrayList.java:414)
	at cs601.proxy.ClientHandler.run(ClientHandler.java:45)
	at java.lang.Thread.run(Thread.java:744)