How to retrieve all signatures in a signed document

override fun onDocumentLoaded(document: PdfDocument) {
    // This will return all signed signature form fields in the document.
    val signatureFormFields = document.documentSignatureInfo.signatureFormFields

    for (signatureFormField in signatureFormFields) {
        val signatureInfo = signatureFormField.signatureInfo
        // Process the signature information.
        ...
    }
}

@Override
public void onDocumentLoaded(@NonNull PdfDocument document) {
    // This will return all signed signature form fields in the document.
    List<SignatureFormField> signatureFormFields = document.getDocumentSignatureInfo().getSignatureFormFields();

    for (SignatureFormField signatureFormField : signatureFormFields) {
        DigitalSignatureInfo signatureInfo = signatureFormField.getSignatureInfo();
        // Process the signature information.
        ...
    }
}

lifecycleScope.launch {
    // This will return all form elements in the document.
    val formElements = document.formProvider.getFormElements()
        // Filter all signature form elements and cast them.
        .filterIsInstance<SignatureFormElement>()
        // This will create a list of all form elements with a signature on them.
        .filter { signatureFormElement -> signatureFormElement.getOverlappingSignature() != null }
    // A list of all form elements with ink or stamp signatures on them, or an empty list if there are none.
}

// `getFormElements()` and `getOverlappingSignature()` are suspend functions. `runBlocking()` waits
// for them to finish, so only call this on a worker thread.
try {
    // This will return all form elements in the document.
    List<? extends FormElement> allFormElements = BuildersKt.runBlocking(
        EmptyCoroutineContext.INSTANCE,
        (scope, continuation) -> document.getFormProvider().getFormElements(continuation));

    List<SignatureFormElement> formElements = new ArrayList<>();
    for (FormElement formElement : allFormElements) {
        // Filter all signature form elements and cast them.
        if (!(formElement instanceof SignatureFormElement)) continue;
        SignatureFormElement signatureFormElement = (SignatureFormElement) formElement;

        // This will create a list of all form elements with a signature on them.
        Annotation signature = BuildersKt.runBlocking(
            EmptyCoroutineContext.INSTANCE,
            (scope, continuation) -> signatureFormElement.getOverlappingSignature(continuation));
        if (signature != null) {
            formElements.add(signatureFormElement);
        }
    }
    // A list of all form elements with ink or stamp signatures on them, or an empty list if there are none.
} catch (InterruptedException e) {
    Thread.currentThread().interrupt();
}