Optimizing memory leakage in JavaFX

Question

I have written a piece of code, to make letters appear and fly as I write them. The problem it consumes a lot of memory.

I already optimized it a little bit by

Sharing the path object and update its parameters in listeners.
Calling gc each time a new letter is printed

But it still uses a lot of memory, so any ideas about how to reduce its memory utilization ?

Thanks in advance.



    package sample;

    import javafx.animation.PathTransition;
    import javafx.application.Application;
    import javafx.scene.Scene;
    import javafx.scene.layout.Pane;
    import javafx.scene.paint.Color;
    import javafx.scene.shape.LineTo;
    import javafx.scene.shape.MoveTo;
    import javafx.scene.shape.Path;
    import javafx.scene.text.Font;
    import javafx.scene.text.Text;
    import javafx.stage.Stage;
    import javafx.util.Duration;

    public class Main extends Application {

        public static void main(String[] args) {
            launch(args);
        }

        @Override
        public void start(Stage primaryStage) throws Exception {
            Pane root = new Pane();
            Scene scene = new Scene(root);
            root.setCache(false);
            primaryStage.setTitle("Hello World");
            primaryStage.setScene(scene);


            Path path = new Path();
            root.widthProperty().addListener((observableValue, oldSceneWidth, newSceneWidth) -> SetPathElements(path, root));
            root.heightProperty().addListener((observableValue, oldSceneWidth, newSceneWidth) -> SetPathElements(path, root));


            Duration duration = Duration.millis(1000);

            scene.setOnKeyPressed(event -> {
                System.gc();

                Text textNode = new Text(event.getText());
                textNode.setFont(Font.font(50));
                textNode.setFill(Color.ORANGE);
                root.getChildren().add(textNode);


                PathTransition pathTransition = new PathTransition();
                pathTransition.setDuration(duration);
                pathTransition.setPath(path);
                pathTransition.setCycleCount(1);

                pathTransition.setNode(textNode);
                pathTransition.setOnFinished(event1 -> {
                    root.getChildren().remove(textNode);
                    pathTransition.setNode(null);
                    pathTransition.setPath(null);
                    textNode.setFont(null);
                    textNode.setFill(null);
                });
                pathTransition.play();


            });
            primaryStage.show();
        }

        private void SetPathElements(Path path, Pane root) {
            path.getElements().clear();
            double w = root.getWidth();
            double h = root.getHeight();
            path.getElements().add(new MoveTo(w / 2, h));
            path.getElements().add(new LineTo(w / 2, -40));
        }
    }

EDIT #1

OS: Arch Linux 64-bit Platform: Intel i7-3rd generation, 8 GB ram IDE : Intellij JDK : 1.8.0_102

Proof of leak : After typing around 100 chars it jumped from 50 MB to 1.3 GB

EDIT #2

I have checked Heap size using jvisualvm and it indicates that the Heap expands greatly but the used portion don't exceed ~50 MB

I am able to run the you application with just 50MB , how you are saying it is consuming lot of memory? — ravthiru, Oct 24 '16 at 23:21
Just keep writing a few letters and the memory will increase. — Shady Atef, Oct 24 '16 at 23:23
@ShadyAtef I also ran this with the max heap set to 50m. If there were a memory leak it would give an out of memory error pretty quickly. I kept typing for a few minutes and it ran fine. What is your evidence there is a memory leak here? — James_D, Oct 25 '16 at 00:02
There are many Q&A's on how to find a memory leak; e.g. search for "[java] find memory leak". (Native memory leaks are a bit more tricky ...) But first you need clear evidence that there >>is<< a leak ... otherwise you will be wasting your time looking for something that doesn't exist. — Stephen C, Oct 25 '16 at 00:33
How much memory does it use? What OS and hardware do you use? — Itai, Oct 25 '16 at 05:22
"Calling gc each time a new letter is printed": It is usually a bad idea to mess around with the garbage collector. Let it do it's work without interfering, it is optimized for that. — Henry, Oct 25 '16 at 11:06
@Henry, Following your advice, the heap size is almost stable at 100 MB, but the system monitor still reports memory increase while typing. Also jvisualvm sampler reports the used memory is about 20 MB, so there is huge difference between what system monitor reports and what jvisualvm reports — Shady Atef, Oct 25 '16 at 11:17
@ShadyAtef - There is a memory leak in JavaFX with Mesa >=11.0 (meaning any up to date Linux distribution). JavaFX developers say it's a bug in Mesa, but I couldn't find a bug report in Mesa (nor could I file one, as I don't know how to reproduce it outside of JavaFX). The only solutions as of now are - 1. Use an older Linux (the key is having Mesa 10 or lower); 2. Use an NVidia GPU - they have their own OpenGL implementation and don't rely on Mesa. 3. Use Windows. — Itai, Oct 25 '16 at 11:48
@sillyfly, yes I have run the code with bumblebee optirun and it worked with max memory ~140 MB and no leaks Thank you. — Shady Atef, Oct 25 '16 at 11:51
@sillyfly, write your comment as an answer, you deserve the points — Shady Atef, Oct 25 '16 at 12:00

score 5 · Accepted Answer · edited May 23 '17 at 11:54

There is a memory leak in JavaFX with Mesa >=11.0 (meaning any up to date Linux distribution). JavaFX developers say it's a bug in Mesa, but I couldn't find a bug report in Mesa (nor could I file one, as I don't know how to reproduce it outside of JavaFX).
The only solutions as of now are -
1. Use an older Linux (the key is having Mesa 10 or lower)
2. Use an NVidia GPU - they have their own OpenGL implementation and don't rely on Mesa.
3. Use Windows.

Update (November 2016)
This issue seems to have been resolved in newer versions of Mesa and/or X.org. Updating to Mesa 13.0 and X.org >=1.18.4 should solve this issue.

Optimizing memory leakage in JavaFX

EDIT #1

EDIT #2

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