Questions tagged [java]

Java is a programming language.

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5
votes
2answers
4k views

How do I create an offline transaction in java to broadcast via blockchain.info?

Blockchain.info has a PushTX API. How do I create & sign a raw transaction in Java for use in this API? Should I use bitcoinj? Are there any code samples?
7
votes
1answer
4k views

How to sign raw transaction given a private key and SHA hash (in java)

I have followed the instructions here to build my own bitcoin transaction. Redeeming a raw transaction step by step example required Currently my code can create a transaction and compute the SHA ...
3
votes
1answer
3k views

Generating private keys in Java

I'm looking for a way to generate private keys in Java. I'd like to make this a standalone program, so I'd rather not use a library like bitcoinj. From my research I've only seen people recommend ...
7
votes
9answers
7k views

How to communicate between Java and bitcoind?

I am having problems communicating between Java and bitcoind - every JSON RPC library I try has some issues. Can anyone provide a working implementation of even the most basic JSON RPC communication ...
1
vote
1answer
150 views

Errors when building/sending multisig transactions

Going by the example here: https://bitcoinj.github.io/working-with-contracts I believe I've done everything correctly. Yet my program fails either to propagate correctly or because of a tx error and ...
5
votes
1answer
579 views

Test Network Genesis Block

I am using BitcoinJ for my java application which fetches the test network's genesis block. I referred to the basics mentioned at JavaWorld and BitcoinJ's Google Code wiki. I am able to get it ...
3
votes
1answer
2k views

How can I create a raw transaction in hex format with Bitcoinj?

How can I create a raw transaction when I'm given the input scripts, input indexes, input txids, output script, output address and output amount? The method below works but it requires the method ...
3
votes
1answer
2k views

Bruteforce bitcoin address - I know the words + public address but not the order

I have a long list of 1million+ permutations of a 12 word BIP39 seed. How can I try them all on a bitcoin address? edit: I know the address and the 12 words but i don't know the order of the words
3
votes
2answers
229 views

Accept payments on someone else's behalf without being able to spend them

TL;DR I wish to store some sort of key in my application for each vendor account that allows for my application to generate a receiving address for clients to make payments to. I am writing some ...
3
votes
1answer
1k views

Bitcoind returning "Invalid JSON-RPC 2.0 response"?

I am starting to use a basic implementation of Bitcoin JSON RPC (dzhuvinov library), and I am getting a strange result. Here is my code: public static void main(String[] args) { URL serverURL = ...
2
votes
3answers
2k views

Convert between String/Hex/Byte in Java for sha256 - wrong format?

I am trying to convert a bitcoin address and have the following code from here (Calculate Segwit address from public address, 2nd answer): Step1: $ printf 1L88S26C5oyjL1gkXsBeYwHHjvGvCcidr9 > adr....
1
vote
2answers
1k views

How do i parse the zeroMQ messages in java?

This is the code that i have. I receive messages from the zeroMQ however a hashtx message for example looks like this --> "hashtx �����v����|(8d �!��v��&�-�k�". Any help in turning that into a ...
1
vote
2answers
1k views

JAVA JSON-RPC for Litecoin

I am looking for Java Json-Rpc for Litecoin or any implementation for Litecoin
0
votes
1answer
58 views

API for automatical buying and selling coins in Java [closed]

I need to create a simple bot for buying and selling coins and the programming language needs to be Java due to some technical specifications. These are the functions which I need from that API: buy(...
0
votes
2answers
231 views

Verify Bitcoin Transaction

Following the great post [Redeeming a raw transaction step by step example required, I came up with code below but the verification failed. // pubkeyBytes, len: 65 // ...
0
votes
2answers
1k views

generate wallet addresses from extended public key

i am trying to generate addresses from Extended Public Key using bitcoinj but can't figure out, how can i possibly do this. i need those addresses for watch-only wallet, those addresses were ...