get-smart-contract-bytecode.md

Get smart contract bytecode

ContractByteCodeQuery() returns the bytecode for a smart contract instance.

Constructor	Description
ContractByteCodeQuery()	Initalizes a ContractByteCodeQuery object

new ContractByteCodeQuery()

Basic

Method	Type	Description
setContractId(<contractId>)	ContractId	The ID for the contract for which the bytecode is requested

Example

{% tabs %} {% tab title="Java" %}

ClassLoader cl = CreateStatefulContract.class.getClassLoader();

Gson gson = new Gson();

JsonObject jsonObject;

try (InputStream jsonStream = cl.getResourceAsStream("stateful.json")) {
    if (jsonStream == null) {
        throw new RuntimeException("failed to get stateful.json");
    }

    jsonObject = gson.fromJson(new InputStreamReader(jsonStream), JsonObject.class);
}

String byteCodeHex = jsonObject.getAsJsonPrimitive("object")
    .getAsString();
byte[] byteCode = byteCodeHex.getBytes();

// `Client.forMainnet()` is provided for connecting to Hedera mainnet
Client client = Client.forTestnet();

// Defaults the operator account ID and key such that all generated transactions will be paid for
// by this account and be signed by this key
client.setOperator(OPERATOR_ID, OPERATOR_KEY);

// default max fee for all transactions executed by this client
client.setMaxTransactionFee(new Hbar(100));
client.setMaxQueryPayment(new Hbar(10));

// create the contract's bytecode file
TransactionId fileTxId = new FileCreateTransaction()
    // Use the same key as the operator to "own" this file
    .addKey(OPERATOR_KEY.publicKey)
    .setContents(byteCode)
    .execute(client);

TransactionReceipt fileReceipt = fileTxId.getReceipt(client);
FileId newFileId = fileReceipt.getFileId();

System.out.println("contract bytecode file: " + newFileId);

TransactionId contractTxId = new ContractCreateTransaction()
    .setBytecodeFileId(newFileId)
    .setGas(100_000_000)
    .setConstructorParams(
        new ContractFunctionParams()
            .addString("hello from hedera!"))
    .execute(client);

TransactionReceipt contractReceipt = contractTxId.getReceipt(client);
ContractId newContractId = contractReceipt.getContractId();

System.out.println("new contract ID: " + newContractId);

byte [] byteCodeQuery = new ContractBytecodeQuery()
    .setContractId(newContractId)
    .execute(client);

System.out.println("Length " + byteCodeQuery.length);

{% endtab %}

{% tab title="JavaScript" %}

const byteCodeQuery = new ContractBytecodeQuery()
    .setContractId(newContractId)
    .execute(client);

{% endtab %} {% endtabs %}