Java Timer

I'm trying to use a timer to schedule a recurring event in an application. However, I want to be able to adjust the period at which the event fires in real time (according to the users input).

For example:

public class HelperTimer extends TimerTask
{
    private Timer timer;
    //Default of 15 second between updates
    private int secondsToDelay = 15;

    public void setPeriod(int seconds)
    {
        this.secondsToDelay = seconds;
        long delay = 1000; // 1 second
        long period = 1000*secondsToDelay; // seconds
        if (timer != null) 
        {
            timer.cancel();
        }
        System.out.println(timer);
        timer = new Timer();
        System.out.println(timer);
        timer.schedule(this, delay, period);
    }
    public int getPeriod()
    {
        return this.secondsToDelay;
    }
}

I then start a new instance of this class and call its set period function. However, when I do that, I get an Illegal state exception. You can see the System.out.println(timer); in there because I'm checking, and yep sure enough, they are two different timers... so why am I getting an IllegalStateException when I try to run a schedule call on a brand new Timer instance!?!?!?!

java.util.Timer@c55e36
java.util.Timer@9664a1
Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException: Task already scheduled or cancelled
    at java.util.Timer.sched(Unknown Source)
    at java.util.Timer.schedule(Unknown Source)
    at HelperTimer.setPeriod(HelperTimer.java:38)