How to add mask to image when replacing images in pdf with pdfbox

Question

I need to replace the images in the PDF document which I can do. However, after extracting and replacing the resource image object, PDF images become corrupted if there is a soft mask or mask(stencil image) in the image, mask is lost.

This is my code (used pdfbox via python with jpype):

for page in pages:
    resources = page.getResources()
    if resources:
        pageImages = resources.getXObjectNames()
        for c in pageImages:
            imageObj = resources.getXObject(c)
            if isinstance(imageObj, PDImageXObject):
                bImage = imageObj.getImage()
                suffix = str(imageObj.getSuffix())
                tmp = tempfile.NamedTemporaryFile(suffix="." + suffix, mode="wb")
                out = FileOutputStream(tmp.name)
                if bImage.getColorModel().hasAlpha():
                    target = BufferedImage(bImage.getWidth(), bImage.getHeight(), BufferedImage.TYPE_INT_RGB)
                    g = target.createGraphics()
                    g.fillRect(0, 0, bImage.getWidth(), bImage.getHeight())
                    g.drawImage(bImage, 0, 0, None)
                    g.dispose()
                    ImageIOUtil.writeImage(target, suffix, out)
                else:
                    ImageIOUtil.writeImage(bImage, suffix, out)
                
                newImage = PDImageXObject.createFromFile(tmp.name, pdf)
                resources.put(c, newImage)
                tmp.close()

In the above example code even if i didn't touch extracted image and immediately replace it with extracted one if image has mask it's gone after that. I can get smask like this to check:

imageObj.getSoftMask()

How can i replace image and apply original image mask to newImage PDImageXObject using pdfbox? There is "applyMask" function in PDImageXObject but it is private.