Java set jscrollpane scroll not working

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Java

image

desktop

I have a method that change the image size and set its scroll position. Both function is working but when I put it in a single call like this

setZoomFactor(1.5);
setScrollPosition(new Point(500, 500)); //lets say this will display the center of the image.

it will zoom the image but not position it. It is working when I put the 2 in separate button and click it one by one. Is one of the line in setZoomFactor runs in thread and continuing to next line? Need an advice. Thank you.

//CODE FOR ZOOMING AND POSITIONING
public void setZoomFactor(double zoomFactor) {
    if(IMAGE_FOUND && image != null && this._zoomFactor != zoomFactor) {
        this._zoomFactor = zoomFactor;
        width = originalWidth;
        height = originalHeight;
        double newwidth = width * zoomFactor;
        double newheight = height * zoomFactor;
        if(newwidth > 3 && newheight > 3) {
            disposeImage();
            image = ImageUtil.scale((BufferedImage) origImage, newwidth, newheight, _antiAlias);
            garbageCollect();
        }
        jLabel1.setIcon(new ImageIcon(image));
        garbageCollect();
    }
}

public void setScrollPosition(Point position) {
    setScrollX(position.x);
    setScrollY(position.y);
}

public int getScrollX() {
    return jScrollPane1.getHorizontalScrollBar().getValue();
}

public void setScrollX(int scroll) {
    jScrollPane1.getHorizontalScrollBar().setValue(scroll);
}

private void garbageCollect() {
    Runtime.getRuntime().gc();
    System.gc();
}

private void disposeImage() {
    if(image != null) image.flush();
    image = null;
    jLabel1.setIcon(null);
    garbageCollect();
}

What I have tried:

I tried putting the 2 method calls an different buttons and it works. I think its because of the delay between clicking.