Java.util.Date（）行为

Question

我期待下面的代码在365天前打印今天的日期和日期

public static void main(String[] args) {
    long YEAR_IN_MILLIS = 365 * 24 * 60 * 60 * 1000;
    Date curDate = new Date();
    System.out.println("Todays date: " + curDate);
    System.out.println("365 days ago: " 
                     + new Date(System.currentTimeMillis() - YEAR_IN_MILLIS));
}

然而它打印

Todays date: Tue Jan 12 17:22:19 PST 2016
Date 365 days back: Sat Dec 26 16:41:50 PST 2015

我对以下数学不正确感到惊讶？

long YEAR_IN_MILLIS = 365 * 24 * 60 * 60 * 1000;