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Questions tagged [web3-java]

For the web3j java library and related Java issues

Ethereum client library for Java (web3j). Web3j provides code generation tools for Java and Android applications to deploy and interact with smart contracts on the blockchain.

Documentation: https://docs.web3j.io/latest/

Note - This is NOT for web3js, which is the JavaScript version of the Ethereum client library.

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Smart Contract in Geth using web3j

I am trying to deploy my solidity smart contract on the ethereum testrpc network. This is my solidity contract: pragma solidity ^0.4.11; contract Fibonacci { event Notify(uint input, uint result); function fibonacci(uint number) constant…
JokerKnight
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Generating Ethereum wallets with 10 threads in Java freezes computer

I'm trying to create 100k ethereum wallets for test purposes. All should use same pass phrase, because it doesn't matter right now. I launched this code with 10 threads and it froze my macbook, I had to restart it. 3 thread somewhat work, but it's…
Gintas_
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Java "InvalidAlgorithmParameterException"?

Currently i am using web3j to create an account in my private block chain. Like: Web3j web3 = Web3j.build(new HttpService()); Web3ClientVersion web3ClientVersion; String walletFileName = WalletUtils.generateFullNewWalletFile("password",new…
Abhishek saini
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android web3j not connecting to testrpc

very simply I am following the web3j set up on the website, and when trying to get the latest version back to test it is connected to testrpc it throws a SocketException. It says on the website that new HttpService() defaults to localhost:8545 which…
B.K Lewis
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web3j not working with contract function?

This is my simple contract in my private network contract AB { /* This creates an array with all balances */ mapping (address => uint256) public balanceOf; /* Initializes contract with initial supply tokens to the creator of the…
Abhishek saini
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Web3j Solidity Generate Command Not Working

I believe I have everything set up correctly as other Web3j and solc commands have been working fine. However, Following the instructions here: https://docs.web3j.io/smart_contracts.html#deploying-and-interacting-with-smart-contracts to create the…
Cameron
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Web3j new account transacting with testrpc

I'm new to blockchain development. Currently, I'm learning the Ethereum platform and it sounds a very good environment to start with. I tested the web3j library on my Android application and it works fine. I used the following code to connect to my…
Brad Boil
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How can I get a private key from mnemonic phrase via *web3j*

I need to have a private key to load a smartcontract. How can I get a private key from mnemonic phrase via web3j API to pass the private key to load a smart contact? Web3j version is 4.9.8
b3lowster
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How to add web3j to my project in NetBeans

I'm trying to use web3j (https://github.com/web3j/web3j) and I can't figure out how. I know Java (I've developed android apps in android studio) but not netbeans. Though I haven't touched Java in forever. I am familiar with building and interacting…
Chris
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Blockchain POC on DApps in Java

I wanted to develop a web DApplication using Ethereum, Infura, web3J.. can you share your inputs to quickStart, I see more theoretical stuff & don't found any practical examples to step forward using web3j.. I want to store a user earned points on…
Rohith Varala
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