getTransaction error

[bliplink]

public ConfirmedTransaction getTransaction(String signature, Commitment commitment) throws RpcException { List<Object> params = new ArrayList<>(); params.add(signature); Map<String, Object> parameterMap = new HashMap<>();

    if (commitment != null) {
        parameterMap.put("commitment", commitment); //update  parameterMap.put("commitment", commitment.getValue());
    }

    parameterMap.put("maxSupportedTransactionVersion", 0);
    params.add(parameterMap);
    return client.call("getTransaction", params, ConfirmedTransaction.class);
}