Android :: Wake Lock / Phone Restarting Randomly

I have a service which holds on to a wakelock and the code is similar to this,
public class WakeLockService extends Service {
PowerManager.WakeLock wl;
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub return null;
} public void onCreate() {
PowerManager pm = (PowerManager) getSystemService (Context.POWER_SERVICE);
wl = pm.newWakeLock (PowerManager.PARTIAL_WAKE_LOCK, "My Tag");
wl.acquire();
} public void onDestroy() {
wl.release();
}

For past two days, my phone has been restarting randomly. Today it was worse, it kept restarting until I uninstalled the app. I tried to search about this behaviour online and found that too many wakelocks may coz the phone to restart. Can there be any other reason? Is the above code right? Should make wl as a final variable? Does the service call onDestroy method when phone shuts down? I am using a broadcastreceiver to start my service at boot up as well.