The updateProgress methods of Task are spec'd such that the workDone must be less than or equal to max, or an IllegalArgumentException is thrown. This is sometimes a pain. The following Service would sometimes throw an exception based on timing where the "delta" ended up being 1 more than max:


                final Service<Void> service = new Service<Void>() {
                    final Service<Void> svc = this;
                    @Override protected Task<Void> createTask() {
                        return new Task<Void>() {
                            @Override protected Void call() throws Exception {
                                long millis = 1000;
                                long start = System.currentTimeMillis();
                                long delta = 0;
                                while (delta < millis) {
                                    delta = System.currentTimeMillis() - start;
                                    Thread.sleep(1);
                                    updateProgress(delta, millis);
                                }
                                return null;
                            }
                        };
                    }
                };


Instead, lets just spec that a call to updateProgress where workDown > max will be clamped to max.