Hi resource usage or it is normal?

Question

Hi, i have started experimenting with javafx. i liked it so much. but i noticed it consumes a lot of memory in some cases. Below code generates around 2000 Bubble object. But if you extend the number it gives an out of memory exception. i think this is a pretty small number for occupying 64MB heap. Any comments or suggestions?
public class Bubble extends CustomNode{
    public var cap:Integer;
    public override function create(): Node {
        return Group {
            content: [
                Circle{ opacity:0.1 radius: cap}
                Circle{ opacity:0.2 radius: cap/2}
                Circle{ opacity:0.4 radius: cap/3}
function generate(): Bubble[] {
    var rand:Random = new Random();
    var bubbles: Bubble[]=[];
    for(i in [0..100]) {
        def bubble = Bubble  {
            layoutX:rand.nextInt(300)+100
            layoutY:rand.nextInt(300)+100
            cap: rand.nextInt(10)+10
        insert bubble into bubbles;
    return bubbles;
Stage {
    title: "Dark Cloud"
    width: 500
    height: 500
    scene: Scene {
        content: [
            for(i in [0..20])
                generate()
}

Answer 1

Somehow, it illustrates the power and limitations of JavaFX design.
I also code in Processing, which is more or less Java code using an easy to use graphics library.
Unlike JavaFX, Processing is low level (in 2D), ie. it is a canvas on which you draw primitives. If you want Rectangles, Ellipses or other more or less complex nodes, you have to code them yourself.
The advantage is that you can make tighter code: Your Bubble class creates an Integer, a Group and three Circle, that's 4 Nodes, coming with all their variables, Boolean, Number, sequence of Transformation, various Bounds, Cursor, Effect, functions (the variables, not the members), etc. Even set to their default, that's a lot of memory, even more as a Boolean isn't a Java boolean.
While in Processing, you would do the same class with an int for the cap, two for the coordinates, perhaps a static int for the color if shared by all bubbles, etc. I bet it would take much less memory to do your test than JavaFX does.
Granted, JavaFX is then ready out of the box to do effects and transforms, handle clicks, etc. But sometime, for simple dumb objects, it is just overkill...
So maybe JavaFX isn't suited for applications that are commonplace in Processing, like handling million of particles, unless using tricks like making its own canvas and using bitmap drawing...