I'm trying to get the raw blocks with bitcoinj. I use Block.bitcoinSerialize() to get the bytes of each block when it is downloaded, but does not include transactions. How can I get the full raw block?

2 Answers 2


I have found a temporary solution:

BlockStore blockStore = new MyCustomBlockStore(NETWORK_PARAMETERS);

blockChain = new BlockChain(NETWORK_PARAMETERS, blockStore);

PeerGroup peerGroup = new PeerGroup(NETWORK_PARAMETERS, blockChain);
peerGroup.addPeerDiscovery(new PeerDiscovery() {
    private final PeerDiscovery normalPeerDiscovery = new DnsDiscovery(NETWORK_PARAMETERS);

    public InetSocketAddress[] getPeers(long services, long timeoutValue, TimeUnit timeoutUnit) throws PeerDiscoveryException {
        final List<InetSocketAddress> peers = new LinkedList<InetSocketAddress>();
            peers.addAll(Arrays.asList(normalPeerDiscovery.getPeers(services, timeoutValue, timeoutUnit)));
            InetSocketAddress[] isas = new InetSocketAddress[0];
            return peers.toArray(isas);

    public void shutdown() {

peerGroup.startBlockChainDownload(new PeerDataEventListener() {
    public void onBlocksDownloaded(Peer peer, Block block, @Nullable FilteredBlock filteredBlock, int i) {

        List<Transaction> transactionsList = block.getTransactions();
        int transactions = transactionsList == null ? 0 : transactionsList.size();

        long height = peer.getBestHeight() - i;
        //If the block contains transactions, it is likely to be complete.
        Log.e(TAG, "Downloaded block " + height + " with " + transactions + " transactions");

    private void blockUpdate(Block fBlock) throws IOException {
        //TODO: Update blockchain database with the full block.

    public void onChainDownloadStarted(Peer peer, int i) {
        Log.i(TAG, "Started to download chain on peer " + peer);

    public List<Message> getData(Peer peer, GetDataMessage getDataMessage) {
        //Log.i(TAG, "getData from " + peer);
        return null;

    public Message onPreMessageReceived(Peer peer, Message message) {
        //Log.i(TAG, "onPreMessageReceived (" + message.getClass().getSimpleName() + ") from " + peer);
        return message;

In my case, I created a BlockStore that stores the blocks in a SQLite3 database. When I get the complete block, I overwrite the block register with the complete information (transactions, raw block, etc...)


In its default configuration, bitcoinj only downloads filtered blocks and keeps only those transactions that are relevant to the connected wallet(s).

  • Is there a way to change the default configuration to download all blocks fully?
    – Murch
    Apr 5, 2017 at 9:01

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