private long getPasswordAge(ModeledUser user) {

        // If no password was set, then no time has elapsed
        PasswordRecordModel passwordRecord = user.getPasswordRecord();
        if (passwordRecord == null)
            return 0;

        // Pull both current time and the time the password was last reset
        long currentTime = System.currentTimeMillis();
        long lastResetTime = passwordRecord.getPasswordDate().getTime();

        // Calculate the number of days elapsed since the password was last reset
        return TimeUnit.DAYS.convert(currentTime - lastResetTime, TimeUnit.MILLISECONDS);
        
    }
Returns the age of the given user's password, in days. The age of a
user's password is the amount of time elapsed since the password was last
changed or reset.

@param user
    The user to calculate the password age of.

@return
    The age of the given user's password, in days.
extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/security/PasswordPolicyService.java