java.util.Date before() function gives false for dates before 1 month

Question

Here is a code snippet:

public static void main(String[] args) {
        // TODO code application logic here
        long oneMonthAgo=30*24*60*60*1000;
        Date now = new Date();
        Date twf=new Date(now.getTime()-oneMonthAgo);
        System.out.println(twf.before(now));
    }

This outputs false

While this code snippet:

public static void main(String[] args) {
        // TODO code application logic here
        long twentyDaysAgo=20*24*60*60*1000;
        Date now = new Date();
        Date twf=new Date(now.getTime()-twentyDaysAgo);
        System.out.println(twf.before(now));
    }

Output: True

Isnt it strange enough ?