I am using Web3j to deploy and interact with a contract on Azure consortium blockchain.

Connecting to Azure consortium blockchain RPC endpoint

Web3j web3 = Web3j.build(new HttpService("http://***.cloudapp.azure.com:8545"));

Unlocking my account from my wallet file

Credentials credentials = WalletUtils.loadCredentials("mypassword", "path/to/mywallet");

Deploying contract from web3j smart contract wrapper

 Future<MySmartContract> contract = MySmartContract.deploy(
   new Uint256(10000L));

Printing the contract address


Under the hood, Web3j would call


but the result would always be "{"jsonrpc":"2.0","id":1,"result":null}[\n]"

Essentially, I am guessing the transaction is submitted to the blockchain, but the blockchain does not mine this transaction. I have tried this on Ethereum testnet and it works. I am wondering whether there are debugging tools or ways to monitor the azure consortium blockchain, and possible solutions to this issue.

2 Answers 2


Turns out it was gas price too low (bigger than the largest integer). Then it starts mining an empty contract, that turned out to be gas limit too low.

  • Could you please accept this answer, otherwise community will bump it over and over again? Commented Apr 22, 2019 at 14:09

Good that you managed to find a solution!

Geth offers proof-of-authority now, which allows to spin up private chains without proof-of-work. Not something of much value but worth mentioning I think. We chose it over Azure for our proof-of-concept on ethereum.

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