i have this code

 @Override
    public void onBackPressed() {
        if (muPDFCore != null && muPDFCore.hasChanges()) {
            DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    if (which == AlertDialog.BUTTON_POSITIVE) {
                        Log.d("PDFVieweeeeeee", "Attempting to save document...");
//                        OnAcceptButtonClick(, true);
                        muPDFCore.save();
                    }
                    finish();
                }
            };
            AlertDialog alert = mAlertBuilder.create();
            alert.setTitle(com.lonelypluto.pdfviewerdemo.R.string.dialog_title);
            alert.setMessage(getString(com.lonelypluto.pdfviewerdemo.R.string.document_has_changes_save_them));
            alert.setButton(AlertDialog.BUTTON_POSITIVE, getString(com.lonelypluto.pdfviewerdemo.R.string.yes), listener);
            alert.setButton(AlertDialog.BUTTON_NEGATIVE, getString(com.lonelypluto.pdfviewerdemo.R.string.no), listener);
            alert.show();
        } else {
            Log.d("PDFVieweeeeeee", "Attempting to save document.ssss.");
            finish();
        }
    }

in this muPdfcore. save come it save in android 9 and below devices not above devices

 public synchronized void save() {
        this.saveInternal();
    }

private native void saveInternal();

How i can solve it like how to save it in 10 and up devices whichever i did changes i wanna save in same file
if u wanna see full code here is the link
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