<dependencies> <dependency> <groupId>org.web3j</groupId> <artifactId>core</artifactId> <version>3.8.0</version> </dependency> </dependencies> Web3j web3 = Web3j.build(new HttpService("https://rinkeby.infura.io/v3/YOUR_INFURA_API_KEY")); Credentials credentials = WalletUtils.loadCredentials("password", "/path/to/wallet/file.json"); YourSmartContract contract = YourSmartContract.load(contractAddress, web3, credentials, GAS_PRICE, GAS_LIMIT); TransactionReceipt receipt = contract.yourContractMethod(arg1, arg2).send(); if (receipt.isStatusOK()) { } else { }