Convert PPTX to Word in Java

Presentation presentation = new Presentation("presentation.pptx");
try {
    Document document = new Document();
    DocumentBuilder documentBuilder = new DocumentBuilder(document);

    for (ISlide slide : presentation.getSlides()) {
        IImage slideImage = slide.getImage(1f, 1f);
        try {
            ByteArrayOutputStream imageStream = new ByteArrayOutputStream();
            slideImage.save(imageStream, ImageFormat.Png);
            documentBuilder.insertImage(imageStream.toByteArray());
        } finally {
            slideImage.dispose();
        }

        documentBuilder.insertBreak(BreakType.PAGE_BREAK);
    }

    document.save("output.docx");
} finally {
    presentation.dispose();
}