finally{timer.cancel();} not being reached in a transaction

Question

We have the following transaction that sends a heartbeat while it is a running. However in certain situations the heartbeat timer never stops, and the system keeps sending heartbeats even if the transaction is not running. Are we doing something incorrectly here? Is there a more sure shot way of stopping the heart beat timer (other than stopping jboss)?

    @TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
    @Asynchronous
    public void performUpdate(long requestSettingId) throws exception {
        try {
            // At this line a new Thread will be created
            final Timer timer = new Timer();
            // send the first heartbeat
            workerService.sendHeartBeat(requestSettingId);
            // At this line a new Thread will be created
            timer.schedule(new HeartbeatTask(setting.getId()), heartBeatInterval, heartBeatInterval);

            try {
                //Perform update
                //

            } finally {
                // terminate the HeartbeatTask
                timer.cancel();
            } catch (Exception e) {
            //Notify the task owner of the exception   
            }    
        }

    }

Answer 1

You finally block need to belong to the outer try, not to the inner try. If timer.schedule fails then your finally block is never executed. Something like:

    public void performUpdate() throws exception {
    Timer timer = null;
    try {
        // At this line a new Thread will be created
        timer = new Timer();

        try {
            timer.cancel();
        } catch (Exception e) {
            //Notify the task owner of the exception
        }
    } finally {
        if ( timer != null ) timer.close();
    }
}