staticについて

public class Account {
    public static int savings;
    public static int payBack(int sum) {
        System.out.println("預金残高：" + savings);
        System.out.println("払い戻し料："+ sum);
        savings -= sum;
        return savings;
    }
}

public class AccountMain {
    // 実行メソッド。
    public static void main (String[] args) {
        int money = Integer.valueOf(args[0]);
        Account.savings = 10000;
        System.out.println("Aさん預金残高：" + Account.payBack(money));
        try {
            Thread.sleep(5000); // 5秒間停止
        } catch (InterruptedException e) {
            System.out.println("予期せぬエラーです。");
        }
        System.out.println("Aさん預金残高：" + Account.savings);
    }
}

public class AccountMain2 {
    // 実行メソッド。
    public static void main (String[] args) {
        int money = Integer.valueOf(args[0]);
        Account.savings = 25000;
        System.out.println("Bさん預金残高：" + Account.payBack(money));
        try {
            Thread.sleep(5000); // 5秒間停止
        } catch (InterruptedException e) {
            System.out.println("予期せぬエラーです。");
        }
        System.out.println("Bさん預金残高：" + Account.savings);
    }
}