Questions tagged [ethereumj]

For questions regarding the installation or use of EthereumJ, a Java library that implements the Ethereum protocol.

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55 views

Dev install fails for Python 3.8 when installing py-evm dependencies

When following this guide in the py-evm docs, I get this verbose error when installing dependencies. It appears to be related to mypy and typed-ast, but I don't know enough about these to be able to ...
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1answer
16 views

What happens if the tokenURI api serves a different metadata?

The way to reference the actual payload of the NFT is a centralized endpoint. When I create the NFT I might provision an API with an endpoint that serves a particular piece of data. What's to stop me (...
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1answer
67 views

Transfer not working on buy swaps with ERC20

I am trying to send a percentage of ethereum to my marketing wallet when someone buys or sells my token via uniswap. It seems to work on sells but not on buys... why is that? i get nothing transferred ...
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1answer
42 views

How to decide SPDX license for a smart contract? [closed]

I am not sure how to decide which spdx licence will go with my smart contract. Can anyone help like how decide which spdx licence will be use in a contract.
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Is it possible to do privacy preserving token metadata sharing between Ethereum and a TEE

Is it possible to do a privacy preserving ERC 721 / ERC 1155 token metatadata transfer between Ethereum Layer 1 Smart Contract based Token Vault and a Trusted Execution Environment like Intel SGX or ...
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Cannot import Aave in remix

I tried to load aave in remix by following the below code pragma solidity ^0.6.6; import "https://github.com/aave/flashloan-box/blob/Remix/contracts/aave/FlashLoanReceiverBase.sol"; import &...
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11 views

Why my hash value for separate files is not being rendered?(Ethereum Solidity)

I'm trying to store my files in IPFS and get the hash value and store them in the smart contract.I want to render my hash value in the frontend page. But in the below code the hash value of first ...
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53 views

web3 transaction value always 0

Can anyone explain to me, why the transaction object I receive via web3 always has a value of 0? When I open up the transactionhash in etherscan, it shows under the to field which is named "...
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14 views

Remix Deployment

I'm deploying an erc20 token on the ethereum mainnet and so far every time I attempt a deploy the console displays "Creation of DappToken pending..." and an etherscan link that leads to &...
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1answer
160 views

Is IPFS mandatory for NFT

Is it mandatory to use IPFS for file storage and use its hash in metadata for NFT, What if file is stored on s3 and we save its sha256 or md5 in metadata? Hash will be same until file content is ditto,...
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13 views

Block timestamp or block number as short time check [duplicate]

Which one is better to check short period of time change 60seconds block.timestamp or block.number?
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2answers
46 views

Internal transaction [duplicate]

So, I was using Bitbuy to buy and send eth to the wallet of my friend. I dont know how but that transaction finish as internal and it doesnt appear on friends wallet. Does anyone know who needs to do ...
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1answer
49 views

Make Hyperledger Besu sync faster during DOS blocks

I am attempting to sync a full node using Hyperledger Besu and it has slowed down considerably when hitting about block 2,300,000. Geth and Parity can be made faster as this link details to sync these ...
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30 views

I want to fork Ethereum with my own implementation. Like changing name or block size or something like this [duplicate]

I'm such a noob or may be this is a noob type question i just want to fork Ethereum in go(maybe in another language) with my own implementation. Anyone can guide me about that?? Is there any relevant ...
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162 views

How to solve Transaction has been reverted by the EVM , In need of a solution based on my code?

I have been using ropsten with infura. SMART CONTRACT contract Don { struct Details { uint id; string name; string dob; ...
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1answer
31 views

Why the need for different tokens?

So, ERC20 tokens are bought depositing equivalent Price = amount to be bought*price of tokens) in eth to the smart contract eth address. So lets talk about BAT ERC20 token: If I am verified BAT ...
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1answer
10 views

How many parallel read/write request single contract can handle each second

I need this reply for a large user base prospective, where each second too many request going to that particular contract , so the question is what is write per second limit and what is read per ...
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1answer
644 views

how to call "selfdestruct" if not written in contract, as documentation says its possible

as mentioned in documentation "Even if a contract’s code does not contain a call to selfdestruct, it can still perform that operation using delegatecall or callcode." so my question is how ...
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1answer
320 views

Smart Contract Application in ASP>NET [closed]

I just have started to learn Smart Contract. I have to design front end in ASP.NET. Can I call Contract from it?
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1answer
217 views

Truffle Migrate

What happens when there is a minor change in the smart contract and I run truffle migrate command. Example: //before contract test{ function display() public returns (string){ return "...
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1answer
83 views

Having a problem compiling a ERC20 token smart contract - Code inside

Basically i'm using a cut and paste erc20 token code from this site: https://hashnode.com/post/how-to-build-your-own-ethereum-based-erc20-token-and-launch-an-ico-in-next-20-minutes-...
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116 views

Just not able to install Web3 through powershell

After reading a lot of articles about how to install Web3j in windows. I also tried following this article : https://kauri.io/generate-a-java-wrapper-from-your-smart-contract/...
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572 views

TypeError: Operator != not compatible with types string storage ref and int_const 0

Im using blockchain technology for the first time, for a college project. Im trying to run a smart contract from Github (in Powershell windows 10). Im unable to compile the contract due the following ...
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1answer
227 views

Im getting the following error: ParserError: Expected primary expression. struct ManagingOrder.Parking memory new_Parking = Parking({

Im using blockchain technology for the first time, for a college project. Im trying to run a smart contract from Github. After debugging the errors shown while compiling the smart contract (in ...
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1answer
36 views

Value of emitted events in App.js

Actually in my App.js I have called my contract function like this: [ this.state.swapcontract.methods.sendFunds(address).send({ from: this.state.account , value:amount}) ] The function is called ...
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1answer
88 views

Can we use secp256r1 to generate valid Ethereum address instead of secp256k1?

We interact with HSM via Graphene to generate EC public/private key for Ethereum blockchain, many tutorials say secp256k1 to generate valid Eth address, however the Graphene supports only secp256r1
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716 views

get event logs and debug trace from eth_call

I am looking for a way to execute a transaction locally (using local geth/parity node) for simulation only, before actually submitting it to blockchain. I know that I can use 'eth_call' RPC call and ...
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1answer
194 views

How to resolve this error in solidity “The constructor should be payable if you send value.”?

In this solidity code the finalizeRequest() is giving a run-time error. Here is the error : Campaign.finalizeRequest(uint256) 0x692...77b3a transact to Campaign.finalizeRequest errored: VM error: ...
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207 views

Not able to decode the input data from transaction using web3j (Java)

I am creating transactions using web3j and passing some private data in that transaction. The transaction is also getting mined . I have subscribed to the mined blocks, where I am fetching the ...
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2answers
51 views

Calling smart contract functions and submitting transacions in BACK-END in high level

I have read some references to create ethereum transactions by a BACK-END server, all in low level, for example, requiring that I control the nonce by myself. Are there safe ways to avoid this control ...
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1answer
180 views

How and when should I use a Ethereum smart contract in document verification process?

First, a student applies for a certificate in his/her University . The University creates his degree certificate . Now , how do I write a smart contract in Solidity so that anyone in blockchain can ...
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2answers
233 views

Cannot install web3 on nodejs

When I try to install web3 using 'npm install ethereum/web3.js --save' command, I get the following error messages- npm ERR! path git npm ERR! code ENOENT npm ERR! errno ENOENT npm ERR! syscall ...
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2answers
200 views

Why am I getting TypeError: Member "balanceOf" not found or not visible after argument?

On line 22 my code is -- require(tokenContract.balanceOf(this) >= _numberOfTokens); This gives the error message TypeError: Member "balanceOf" not found or not visible after argument-dependent ...
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1answer
120 views

Why am I getting a Parse Error in my smart contract after the constructor?

I'm writing a token sale smart contract & my original error was my function had the same name as the contract and I changed it to a constructor because the contract cant have the same name as the ...
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1answer
59 views

Issue Deploying Contract LinkedIn Course - Ethereum: Building Blockchain Decentralized Apps (DApps)

I'm completely new to Ethereum Smart Contracts. I'm following the course on LinkedIn [Ethereum: Building Blockchain Decentralized Apps (DApps)]. I've been able to compile the smart contract as per ...
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1answer
267 views

Use uint40 for time in Solidity?

My question is: Should I use uint40 for time in Solidity? All the examples I've seen use uint256 for time, however, I think it's too wasteful -- while using uint32 is maybe a little aggressive due to ...
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3answers
802 views

web3.eth.sendSignedTransaction executed successfully but never any ETH transferred actually

as you see in below, i the raw transaction has been set by the gas simplify value, the returned value is an implemented transaction hashcode, but never assumed result by this transaction figure out ...
2
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1answer
51 views

How Ethereum HardFork Complete?

When a major change happen in ethereum like Softfork or Hardfork, all nodes may not agree with this. So is this change possible ? Vitalik is creator of Ethereum. But ethereum is totally decentralized, ...
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0answers
48 views

How to run private node on EthereumJ

I would like to run a private node on EthereumJ. I don't know how to start mining on EthereumJ and how to start EthereumJ node. I will be very grateful if someone tell me where to start looking (...
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2answers
886 views

How to convert smallest unit of ERC20 with less than 18 decimals to full coins without rounding errors?

I can just use web3's fromWei function for all token that have 18 decimal places but I'm not sure how to convert token to full token without having to worry about rounding errors. For example convert ...
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0answers
56 views

How to completely empty an Ethereum wallet using W3.py

I have an ethereum wallet, I need to calculate the amount to completely empty the wallet. So currently i calculate the needed gas like this, needed_gas = w3.eth.gasprice * 210000 amount_to_send = ...
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1answer
464 views

Query Ethereum Blockchain for functions return value of a Specified Smart Contract

I want to get smart contract functions return value sent by a specified smart contract within a range of blocks. I found a [manual] working method to achieve this: async function getTxsByAccount(...
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1answer
224 views

Truffle test failing

i am learning solidity contracts and ethereum dapps. I have created a smart contract for creating a ERC20 token on using truffle dev environment. pragma solidity ^0.5.0; contract LearnTokens { ...
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2answers
955 views

How to get the same SHA3 hash as soliditySHA3(ethereumjs-abi) returns using web3.sha3 in js?

I'm trying to hash a message as shown here: function constructPaymentMessage(contractAddress, amount) { return ethereumjs.ABI.soliditySHA3( ["address", "uint256"], [contractAddress, amount],...
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2answers
545 views

Pass specific address in Web3J send method

How to pass specific address in send method in Web3J? For example, using web3 javascript library, we can pass from address like below. contract.someMethod().send({ from: this.props.accounts[0] }) ...
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1answer
13 views

Token Transferring issue to the respective winner

My code has a function which randomly select a subscriber from the list and all of the sum of the tokens should transfer to the winner account address. but unfortunately it is not working for me. ...
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0answers
174 views

How to write a mock method for getting ether balance using Web3j Api. I am trying to mock Web3j and callig EthGetBalance method but I am getting Null

public static BigInteger OriginalMethod(){ // connect to node Web3j web3 = Web3j.build(new HttpService()); // defaults to http://localhost:8545/ // send asynchronous requests to get balance ...
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1answer
119 views

Unable ts start Bootnode, am new to private blockchian, Can anyone tell me what am i missing

bootnode : The term 'bootnode' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path ...
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2answers
2k views

Could not find artifacts for ./Election from any sources

I tried solutions provided in ethereum stack, but nothing worked for me. My smart contract file: pragma solidity ^0.4.15; contract Election { string public candidate; function Eletion () ...
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1answer
765 views

How do I call the burnFrom() function once my contract is deployed?

I'm using the Openzeppelin library in my contract where MyToken is StandardBurnableToken. Once I deploy that and I want to burn a set amount of the initial supply how do I call the function? I don't ...