How to set dynamic return type for rest template

I just want to set the dynamic return type of the object returned by postForObject. This is what I have tried, but its not working.

Object[] decryptedDataArray = restTemplate.postForObject(url, dataToBeDecryptedList.toArray(), Object[].class);

if(decryptedDataArray instanceof DecryptedData[]){
    if (decryptedDataArray != null && decryptedDataArray.length > 0) {
        fieldDataMap = setDecryptedData(fieldDataMap, (DecryptedData[]) decryptedDataArray);
    }
}