MultiChain Developer Q&A - Recent questions tagged bitcoinj

Using Bitcoinj with Multichain

Tue, 28 Jun 2016 15:14:56 +0000

I want to create a blockchain where i can store Hash of a file and timestamp irt and then verify its existence, i saw a video tutorial using Bitcoinj that shows '' Building a document timestamping contracts app in under 30 minutes''

Is it possible to do so using multichian (using bitcoinj or alternantives)?

Is there any leads to help achieve this project ( tutorials . ...)?

Thanks

Options for Multichain SPV client

Thu, 02 Jun 2016 11:32:32 +0000

Hello MultiChain.

In an scenario with a MultiChain network and thousand of potential users I was thinking in generating the users' addresses in a MultiChain node and operate with them using the RPC API from a very lightweight mobile client, but, if I understood well, in this case all the private keys of the users will be in the MultiChain node. Now, I am thinking in the development of an SPV wallet for the users and I would like to know which are the alternatives to do this.

I have read about BitcoinJ for Multichain, that should work if the MultiChain network behaves like the Bitcoin network, but I have a doubt here: does BitcoinJ for Multichain support the custom issued assets and the permission management that Multichan includes?

Apart from BitcoinJ, do you know about other alternatives to implement a Multichain wallet for mobile phones that avoids the storage of the private keys in a network node?

Thanks in advance.

Regards.

bitcoinj to MultiChain bitcoin - connection timeout

Thu, 26 May 2016 05:20:52 +0000

Hi, I cloned a copy of the modified BitcoinJ from: https://github.com/MultiChain/sample-bitcoinj.git and followed exactly all the instructions in the README file, including using the sample params.dat file provided (multichain_bitcoin.params.dat) without any modification ( so, I am running Multichain as a bitcoin network without assets and permissions).

However, I keep getting the following error messages -- it connected but timed-out after 5 seconds. Appreciate your kind advice. I have seen someone asking this before but there was no concrete answer.

Thank you very much.

Regards,

Ying

===========
13:01:34 21 PeerGroup.connectTo: Attempting connection to [128.199.223.47]:8333 (0 connected, 1 pending, 1 max)
13:01:34 22 NioClientManager.handleKey: Successfully connected to /128.199.223.47:8333
13:01:34 22 Peer.connectionOpened: Announcing to /128.199.223.47:8333 as: /bitcoinj:0.14-SNAPSHOT/WalletTemplate:1.0/
13:01:39 23 PeerSocketHandler.timeoutOccurred: [128.199.223.47]:8333: Timed out
13:01:39 23 PeerGroup.handlePeerDeath: [128.199.223.47]:8333: Peer died (0 connected, 0 pending, 1 max)

===========

Error connecting BitcoinJ client to Multichain

Mon, 25 Apr 2016 04:37:38 +0000

I tried to connect BitcoinJ to Multichain, it showed the following error :

11:34:40 20 PeerGroup$7.run: Starting ...
11:34:40 20 PeerGroup$5.go: Localhost peer detected, trying to use it instead of P2P discovery
11:34:40 20 PeerGroup.connectTo: Attempting connection to [127.0.0.1]:8333 (0 connected, 1 pending, 0 max)
11:34:41 21 NioClientManager.handleKey: Successfully connected to /127.0.0.1:8333
11:34:41 21 Peer.connectionOpened: Announcing to /127.0.0.1:8333 as: /bitcoinj:0.14-SNAPSHOT/Prachakij_Wallet:1.0/
11:34:41 21 Peer.processVersionMessage: Connected to 127.0.0.1: version=70002, subVer='/Satoshi:0.10.0/', services=0x1, time=2016-04-25 11:34:41, blocks=436
11:34:41 21 PeerGroup.handleNewPeer: [127.0.0.1]:8333: New peer (1 connected, 0 pending, 1 max)
11:34:41 21 PeerGroup.setDownloadPeer: Setting download peer: [127.0.0.1]:8333
11:34:41 21 DownloadProgressTracker.startDownload: Downloading block chain of size 240.
11:34:41 21 Peer.processMessage: [127.0.0.1]:8333: Received unhandled message: org.bitcoinj.core.GetAddrMessage@5f03bcd2
11:34:41 21 AbstractBlockChain.add: Block does not connect: 00002b83d7a967cd1897edb2c63ec561579b0142fe53bbbbe7691e7d160b3833 prev 00edb9ee9ccd424ea5a5683e89f419d3bce9eee8ef21f94f26cb7dd133a40abe
11:34:41 21 AbstractBlockChain.add: Block does not connect: 000068f7c1d122ef409da58f57a1e71609977a78d33e7586a36cf7957253c757 prev 00002b83d7a967cd1897edb2c63ec561579b0142fe53bbbbe7691e7d160b3833
11:34:41 21 Peer.blockChainDownloadLocked: blockChainDownloadLocked(00002b83d7a967cd1897edb2c63ec561579b0142fe53bbbbe7691e7d160b3833): ignoring duplicated request: 0000bc237efd32b3e50e24e009f79aa82818ec8875497884228e6e1855a399b4

11:25:05 21 AbstractBlockChain.add: Block does not connect: 000033d25e77bec07a6a3a7854910159714c69b3709052bed6e5bce7998d45ea prev 000086961a935a38bdf0507442c71785ab371aafae469908807c55d1ef94f96d
11:25:05 21 Peer.blockChainDownloadLocked: blockChainDownloadLocked(00002b83d7a967cd1897edb2c63ec561579b0142fe53bbbbe7691e7d160b3833): ignoring duplicated request: 0000bc237efd32b3e50e24e009f79aa82818ec8875497884228e6e1855a399b4
11:25:05 21 Peer.blockChainDownloadLocked: java.lang.Throwable
   at org.bitcoinj.core.Peer.blockChainDownloadLocked(Peer.java:1346)
   at org.bitcoinj.core.Peer.endFilteredBlock(Peer.java:1013)
   at org.bitcoinj.core.Peer.processMessage(Peer.java:388)
   at org.bitcoinj.core.PeerSocketHandler.receiveBytes(PeerSocketHandler.java:182)
   at org.bitcoinj.net.ConnectionHandler.handleKey(ConnectionHandler.java:223)
   at org.bitcoinj.net.NioClientManager.handleKey(NioClientManager.java:86)
   at org.bitcoinj.net.NioClientManager.run(NioClientManager.java:122)
   at com.google.common.util.concurrent.AbstractExecutionThreadService$1$2.run(AbstractExecutionThreadService.java:60)
   at com.google.common.util.concurrent.Callables$3.run(Callables.java:95)
   at org.bitcoinj.utils.ContextPropagatingThreadFactory$1.run(ContextPropagatingThreadFactory.java:35)
   at java.lang.Thread.run(Thread.java:745)

BitcoinJ with MultiChain

Tue, 18 Aug 2015 12:23:35 +0000

I discovered a java wrapper to communicate with the bitcoin network, called BitCoinJ.

It applies a mechanism to retrieve DNS seeds to connect to the bitcoin network on startup. I'm just wondering how can I build a client using this wrapper, what seeds or other parameters I need to provide to be able to connect my client to our test multichain network.