FULL PRODUCT VERSION :
java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux oasisdev 2.6.32-504.8.1.el6.x86_64 #1 SMP Wed Jan 28 21:11:36 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux


A DESCRIPTION OF THE PROBLEM :
Gets this:

Exception in thread "JavaFX Application Thread" java.lang.ArrayIndexOutOfBoundsException: 7
at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(AbstractMasterTimer.java:344)

and looking at the code:

        final PulseReceiver receiversSnapshot[] = receivers;
        final int rLength = receiversLength;
        try {
            receiversLocked = true;
            for (int i = 0; i < rLength; i++) {
344: receiversSnapshot[i].timePulse(TickCalculation.fromNano(now));
            }
        } finally {
            receiversLocked = false;
        }

There is a small amount of time that receiversSnapshot[] could be changed before it is locked at line 342 and apparently it is being changed occasionally.

At first it sometimes throws:

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(AbstractMasterTimer.java:344)

Possibly the receiver is null?

The runnables are created by a lambda:

runLater(() -> {
     // do some javafx stuff here
}

    public static void runInPlatform(Runnable runnable) {
        Platform.runLater(() -> {
            final AnimationTimer timer = new AnimationTimer() {
                private int pulseCounter;

                @Override
                public void handle(long now) {
                    pulseCounter += 1;
                    if (pulseCounter > 2) {
                        stop();
                        runnable.run();
                    }
                }
            };
            timer.start();
        });
    }
    
    public static void runLater(Runnable runnable) {
        final PauseTransition pt = new PauseTransition();
        pt.setDuration(Duration.millis(500));
        pt.setOnFinished(actionEvent -> runInPlatform(runnable::run));
        pt.play();
    }



ADDITIONAL REGRESSION INFORMATION:
JDK-8125818 looks like it may be the same issue (different version).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Start a lot animation timers. I started about 9 of them in particular caused an exception to be thrown by one and while sometimes the exception would bubble up occasionally this ArraryIndexOutOfBounds in timePulseImpl would kick off and then I had to stop the process to recover.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I expected the underlying code to know the correct length of the array it was accessing.
ACTUAL -
The underlying code didn't know the correct length of the array it was accessing.

REPRODUCIBILITY :
This bug can be reproduced occasionally.