>>571=573
十分キレイだと思われ。エラー処理が多いだけ。
ちなみに漏れのは、
public class Q523 {
public static void main(String[] args) throws Exception {
if (args.length != 1) { System.err.println("Usage: java Q523 amount"); System.exit(1); }

int amount = Integer.parseInt(args[0]);
int[] types = {10000, 1000, 100, 10, 1};
for (int i = 0; i < types.length; i ++) {
int numMoney = amount / types[i];
System.out.println(types[i] + "yen * " + numMoney);
amount -= types[i] * numMoney;
}
}
}