public class SwingFx extends Application {

    @Override
    public void start(Stage stage) {
        final SwingNode swingNode = new SwingNode();
        createAndSetSwingContent(swingNode);

        Button bt = new Button("Add New");
        bt.setOnMouseClicked(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent mouseEvent) {
                swingNode.setContent(null);
                swingNode.setContent(new TestComp());
            }
        });
        BorderPane borderPane = new BorderPane();
        borderPane.setCenter(swingNode);
        borderPane.setTop(bt);

        stage.setScene(new Scene(borderPane, 200, 150));
        stage.show();
    }

    private void createAndSetSwingContent(final SwingNode swingNode) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JButton bt = new JButton("Click me!");
                bt.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        System.out.println("Click me...");
                    }
                });
                swingNode.setContent(bt);
            }
        });
    }

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


    class TestComp extends JComponent {
        private String[] strArr;

        TestComp() {
            this.strArr = new String[1000];
            for (int i = 0; i < 1000; i++) {
                strArr[i] = Math.random() + "";
            }
        }
    }
}


if we click the "Add New" button which will set content to null at first ,and then add a class with array.
we using Eclispe Memory Analysis tool to analysis the heapdump,and find that the variable lwFrame with type JLightweightFrame increase, and force gc cannot release the memory:
•sun.swing.JLightweightFrame @ 0x921b8e0 - 278,288 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x911bc10 - 278,272 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x915fa88 - 278,208 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8c64068 - 278,200 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x921bd80 - 278,200 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x921d298 - 278,184 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x921c958 - 278,176 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8c642b8 - 278,168 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8d3cef8 - 278,168 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8c63e18 - 278,160 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x91e3af8 - 278,160 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8a20c58 - 278,144 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8c63b80 - 278,144 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8d3d920 - 278,144 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8d3dae8 - 278,144 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x921c220 - 278,144 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x921bb30 - 278,136 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8c63930 - 278,120 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8a207b8 - 278,112 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8a20a08 - 278,112 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x921d738 - 278,104 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x882b810 - 278,096 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x8c649a8 - 278,080 (1.56%) bytes.
•sun.swing.JLightweightFrame @ 0x921cba8 - 278,080 (1.56%) bytes.
 

how can we reset the SwingNode content rightly?