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Questions tagged [ethereumj]

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

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How to mint an erc1155 nft directly to Ethereum blockchain more conveniently?

everyone I want to mint an nft directly to etherium blockchain, is there a easier or cheaper way than usual!? Or any tricks to make it better!?I would appreciate any tip you can get me to make the ...
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How to encrypt a message with multiple public keys for multiple recipients

Is it possible to encrypt a message using multiple Ethereum public keys for multiple recipients of a message, e.g. using https://github.com/pubkey/eth-crypto#encryptwithpublickey , so that each ...
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Why (balance == wei) return false, when I use ethers.js

I'm begin learn ethers.js. I wrote like this const balance = await provider.getBalance("0x862...99"); const ether = ethers.utils.formatEther(balance); const wei = ethers.utils....
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Smart Contract Deployment through React JS

I have deployed multiple contracts using Truffle and Hardhat from a NodeJS project, but I wanted to know if there is a way to deploy smart contracts from ReactJS?
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What this function implies?Why is aAdjusted and bAdjusted?

This function is from uniswap-v3/core/contracts/libraries/Oracle.sol /// @notice comparator for 32-bit timestamps /// @dev safe for 0 or 1 overflows, a and b _must_ be chronologically before or equal ...
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address payable error [duplicate]

please i'm having this issue while trying to deploy my smart contract, please can anyone explain this error for me and how i can solve it Type address is not implicitly convertible to expected type ...
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convert time to utc in Dune Query

I can create a query on the DuneAnalytics site, but the default date format for a field is "2022-02-08 02:44", which downloads to csv as "2022-02-08T02:44:46+00:00". Does anyone ...
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I am getting this problem even though I installed software properties common sudo apt update and all, repositories are not getting installed

$ sudo add-apt-repository -y ppa:ethereum/ethereum Repository: 'deb http://ppa.launchpad.net/ethereum/ethereum/ubuntu/ impish main' More info: https://launchpad.net/~ethereum/+archive/ubuntu/ethereum ...
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How to deduct a specific percent from ERC-20 token on every transaction and send it to multiple wallets?

I would like to ask if there is a template code for the deflationary ERC-20 token that deducts 10% as a tax on buy and sell and how I can distribute this tax income to different wallets? After that ...
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2 answers
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Correct default development blockchain port for truffle

How is the truffle port set when one runs truffle unbox react and then truffle develop ? The documentation states that the default port is 9545 (https://trufflesuite.com/docs/truffle/getting-started/...
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UniswapV3 NFT creation timestamp

Can we get NFT creation timestamp in smart contract from the uniwapV3 smart contracts. I want use position creation timestamp in my smart contract without using orcales.
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Should same contract address be same for multiply users?

OK i know that this is silly question but cant wrap my head around smart contracts .I am using web3j to make a simple android dapp. It should have add deposit, withdraw deposit and get current amount ...
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Opensea-js What is the actual rate limit?

I am wondering what is the actual rate limit of this api? Even with using an api key I get rate limited or throttled requests quiet fast. I can not find any resource about the actual rates they are ...
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How to make a payable transferFrom function that inherits from openzeppelin erc721 contract

I have just finished the crypto zombies tutorial https://cryptozombies.io/ and wanted to get it working locally but also using a solc 0.8.0. Compilation has thrown me lots of errors, many of which I ...
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1 answer
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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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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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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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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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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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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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2 votes
1 answer
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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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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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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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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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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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1 answer
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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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1 answer
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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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1 answer
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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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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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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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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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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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1 vote
1 answer
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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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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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2 votes
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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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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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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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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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-1 votes
1 answer
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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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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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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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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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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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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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3 answers
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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 ...
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2 votes
1 answer
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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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1 vote
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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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2 answers
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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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