关于“Java中的货币转换问题”中输出的质疑

import javax.money.CurrencyUnit;
import javax.money.Monetary;
import javax.money.MonetaryAmount;
import javax.money.convert.CurrencyConversion;
import javax.money.convert.MonetaryConversions;
import java.math.BigDecimal;
import java.text.DecimalFormat;

public class CurrencyConverter {
    public static void main(String[] args) {
        // 定义货币单位
        CurrencyUnit usd = Monetary.getCurrency("USD");
        CurrencyUnit eur = Monetary.getCurrency("EUR");

        // 定义货币金额
        MonetaryAmount usdAmount = Monetary.getDefaultAmountFactory()
                .setCurrency(usd)
                .setNumber(new BigDecimal("1000"))
                .create();

        // 获取货币转换器
        CurrencyConversion conversion = MonetaryConversions.getConversion(eur);

        // 进行货币转换计算
        MonetaryAmount eurAmount = usdAmount.with(conversion);

        // 格式化输出转换结果
        DecimalFormat df = new DecimalFormat("#,##0.00");
        System.out.println("USD: " + df.format(usdAmount.getNumber()) + " -> EUR: " + df.format(eurAmount.getNumber()));
    }
}