Package org.bitcoinj.core

The core package contains classes for network messages like Block and Transaction, peer connectivity via PeerGroup, and block chain management. If what you're doing can be described as basic bitcoin tasks, the code is probably found here. To learn more please consult the documentation on the website.

Interface Summary

Interface	Description
Monetary	Classes implementing this interface represent a monetary value, such as a Bitcoin or fiat amount.
PeerFilterProvider	An interface which provides the information required to properly filter data downloaded from Peers.
TransactionBag	This interface is used to abstract the Wallet and the Transaction
TransactionBroadcast.ProgressCallback	An interface for receiving progress information on the propagation of the tx, from 0.0 to 1.0
TransactionBroadcaster	A general interface which declares the ability to broadcast transactions.
TransactionConfidence.Listener	A confidence listener is informed when the level of TransactionConfidence is updated by something, like for example a Wallet.
UTXOProvider	A UTXOProvider encapsulates functionality for returning unspent transaction outputs, for use by the wallet or other code that crafts spends.

Class Summary

Class	Description
AbstractBlockChain	An AbstractBlockChain holds a series of Block objects, links them together, and knows how to verify that the chain follows the rules of the NetworkParameters for this chain.
Address	Base class for addresses, e.g.
AddressMessage
AddressV1Message	Represents an "addr" message on the P2P network, which contains broadcast IP addresses of other peers.
AddressV2Message	Represents an "addrv2" message on the P2P network, which contains broadcast IP addresses of other peers.
Base58	Base58 is a way to encode Bitcoin addresses (or arbitrary data) as alphanumeric strings.
Bech32	Implementation of the Bech32 encoding.
Bech32.Bech32Data
BitcoinSerializer	Methods to serialize and de-serialize messages to the Bitcoin network format as defined in the protocol specification.
BitcoinSerializer.BitcoinPacketHeader
Block	A block is a group of transactions, and is one of the fundamental data structures of the Bitcoin system.
BlockChain	A BlockChain implements the simplified payment verification mode of the Bitcoin protocol.
BlockLocator	Represents Block Locator in GetBlocks and GetHeaders messages
BloomFilter	A Bloom filter is a probabilistic data structure which can be sent to another client so that it can avoid sending us transactions that aren't relevant to our set of keys.
CheckpointManager	Vends hard-coded StoredBlocks for blocks throughout the chain.
ChildMessage	Represents a Message type that can be contained within another Message.
Coin	Represents a monetary Bitcoin value.
Context	The Context object holds various objects and pieces of configuration that are scoped to a specific instantiation of bitcoinj for a specific network.
DumpedPrivateKey	Parses and generates private keys in the form used by the Bitcoin "dumpprivkey" command.
ECKey	Represents an elliptic curve public and (optionally) private key, usable for digital signatures but not encryption.
ECKey.ECDSASignature	Groups the two components that make up a signature, and provides a way to encode to DER form, which is how ECDSA signatures are represented when embedded in other data structures in the Bitcoin protocol.
EmptyMessage	Parent class for header only messages that don't have a payload.
FeeFilterMessage	Represents an "feefilter" message on the P2P network, which instructs a peer to filter transaction invs for transactions that fall below the feerate provided.
FilteredBlock	A FilteredBlock is used to relay a block with its transactions filtered using a BloomFilter.
FullPrunedBlockChain	A FullPrunedBlockChain works in conjunction with a FullPrunedBlockStore to verify all the rules of the Bitcoin system, with the downside being a large cost in system resources.
GetAddrMessage	Represents the "getaddr" P2P protocol message, which requests network AddressMessages from a peer.
GetBlocksMessage	Represents the "getblocks" P2P network message, which requests the hashes of the parts of the block chain we're missing.
GetDataMessage	Represents the "getdata" P2P network message, which requests the contents of blocks or transactions given their hashes.
GetHeadersMessage	The "getheaders" command is structurally identical to "getblocks", but has different meaning.
GetUTXOsMessage	This command is supported only by Bitcoin XT nodes, which advertise themselves using the second service bit flag.
HeadersMessage	A protocol message that contains a repeated series of block headers, sent in response to the "getheaders" command.
InventoryItem
InventoryMessage	Represents the "inv" P2P network message.
LegacyAddress	A Bitcoin address looks like 1MsScoe2fTJoq4ZPdQgqyhgWeoNamYPevy and is derived from an elliptic curve public key plus a set of network parameters.
ListMessage	Abstract superclass of classes with list based payload, ie InventoryMessage and GetDataMessage.
MemoryPoolMessage	The "mempool" message asks a remote peer to announce all transactions in its memory pool, possibly restricted by any Bloom filter set on the connection.
Message	A Message is a data structure that can be serialized/deserialized using the Bitcoin serialization format.
MessageSerializer	Generic interface for classes which serialize/deserialize messages.
NetworkParameters	NetworkParameters contains the data needed for working with an instantiation of a Bitcoin chain.
NotFoundMessage	Sent by a peer when a getdata request doesn't find the requested data in the mempool.
PartialMerkleTree	A data structure that contains proofs of block inclusion for one or more transactions, in an efficient manner.
Peer	A Peer handles the high level communication with a Bitcoin node, extending a PeerSocketHandler which handles low-level message (de)serialization.
PeerAddress	A PeerAddress holds an IP address and port number representing the network location of a peer in the Bitcoin P2P network.
PeerGroup	Runs a set of connections to the P2P network, brings up connections to replace disconnected nodes and manages the interaction between them all.
PeerSocketHandler	Handles high-level message (de)serialization for peers, acting as the bridge between the org.bitcoinj.net classes and Peer.
Ping	Instances of this class are not safe for use by multiple threads.
Pong	Instances of this class are not safe for use by multiple threads.
PrefixedChecksummedBytes	The following format is often used to represent some type of data (e.g.
RejectMessage	A message sent by nodes when a message we sent was rejected (ie a transaction had too little fee/was invalid/etc).
SegwitAddress	Implementation of native segwit addresses.
SendAddrV2Message	Represents the sendaddrv2 P2P protocol message, which indicates that a node can understand and prefers to receive addrv2 messages instead of addr messages.
SendHeadersMessage	A new message, "sendheaders", which indicates that a node prefers to receive new block announcements via a "headers" message rather than an "inv".
Sha256Hash	A Sha256Hash wraps a byte[] so that Sha256Hash.equals(java.lang.Object) and Sha256Hash.hashCode() work correctly, allowing it to be used as a key in a map.
StoredBlock	Wraps a Block object with extra data that can be derived from the block chain but is slow or inconvenient to calculate.
StoredUndoableBlock	Contains minimal data necessary to disconnect/connect the transactions in the stored block at will.
Transaction	A transaction represents the movement of coins from some addresses to some other addresses.
TransactionBroadcast	Represents a single transaction broadcast that we are performing.
TransactionConfidence	A TransactionConfidence object tracks data you can use to make a confidence decision about a transaction.
TransactionConfidence.Factory
TransactionInput	A transfer of coins from one address to another creates a transaction in which the outputs can be claimed by the recipient in the input of another transaction.
TransactionOutPoint	This message is a reference or pointer to an output of a different transaction.
TransactionOutput	A TransactionOutput message contains a scriptPubKey that controls who is able to spend its value.
TransactionOutputChanges	TransactionOutputChanges represents a delta to the set of unspent outputs.
TransactionWitness
TxConfidenceTable	Tracks transactions that are being announced across the network.
UnknownMessage	Instances of this class are not safe for use by multiple threads.
UnsafeByteArrayOutputStream	An unsynchronized implementation of ByteArrayOutputStream that will return the backing byte array if its length == size().
Utils	A collection of various utility methods that are helpful for working with the Bitcoin protocol.
UTXO	A UTXO message contains the information necessary to check a spending transaction.
UTXOsMessage	Message representing a list of unspent transaction outputs ("utxos"), returned in response to sending a GetUTXOsMessage ("getutxos").
VarInt	A variable-length encoded unsigned integer using Satoshi's encoding (a.k.a.
VersionAck	The verack message, sent by a client accepting the version message they received from their peer.
VersionMessage	A VersionMessage holds information exchanged during connection setup with another peer.

Enum Summary

Enum	Description
AbstractBlockChain.NewBlockType	Indicates whether new Block was on the best chain or not
Bech32.Encoding
Block.VerifyFlag	Flags used to control which elements of block validation are done on received blocks.
BloomFilter.BloomUpdate	The BLOOM_UPDATE_* constants control when the bloom filter is auto-updated by the peer using it as a filter, either never, for all outputs or only for P2PK outputs (default)
InventoryItem.Type
NetworkParameters.ProtocolVersion
PeerGroup.FilterRecalculateMode
RejectMessage.RejectCode
Transaction.Purpose	This enum describes the underlying reason the transaction was created.
Transaction.SigHash	These constants are a part of a scriptSig signature on the inputs.
TransactionConfidence.ConfidenceType	Describes the state of the transaction in general terms.
TransactionConfidence.Listener.ChangeReason	An enum that describes why a transaction confidence listener is being invoked (i.e.
TransactionConfidence.Source	Information about where the transaction was first seen (network, sent direct from peer, created by ourselves).
TransactionInput.ConnectionResult
TransactionInput.ConnectMode

Exception Summary

Exception	Description
AddressFormatException
AddressFormatException.InvalidCharacter	This exception is thrown by Base58, Bech32 and the PrefixedChecksummedBytes hierarchy of classes when you try to decode data and a character isn't valid.
AddressFormatException.InvalidChecksum	This exception is thrown by Base58, Bech32 and the PrefixedChecksummedBytes hierarchy of classes when you try to decode data and the checksum isn't valid.
AddressFormatException.InvalidDataLength	This exception is thrown by Base58, Bech32 and the PrefixedChecksummedBytes hierarchy of classes when you try to decode data and the data isn't of the right size.
AddressFormatException.InvalidPrefix	This exception is thrown by the PrefixedChecksummedBytes hierarchy of classes when you try and decode an address or private key with an invalid prefix (version header or human-readable part).
AddressFormatException.UnexpectedWitnessVersion	This exception is thrown by SegwitAddress when you try to decode data and the witness version doesn't match the Bech32 encoding as per BIP350.
AddressFormatException.WrongNetwork	This exception is thrown by the PrefixedChecksummedBytes hierarchy of classes when you try and decode an address with a prefix (version header or human-readable part) that used by another network (usually: mainnet vs testnet).
ECKey.KeyIsEncryptedException
ECKey.MissingPrivateKeyException
InsufficientMoneyException	Thrown to indicate that you don't have enough money available to perform the requested operation.
PeerException	Thrown when a problem occurs in communicating with a peer, and we should retry.
ProtocolException
PrunedException	PrunedException is thrown in cases where a fully verifying node has deleted (pruned) old block data that turned out to be necessary for handling a re-org.
RejectedTransactionException	This exception is used by the TransactionBroadcast class to indicate that a broadcast Transaction has been rejected by the network, for example because it violates a protocol rule.
SignatureDecodeException
UTXOProviderException
VerificationException
VerificationException.BlockVersionOutOfDate
VerificationException.CoinbaseHeightMismatch
VerificationException.CoinbaseScriptSizeOutOfRange
VerificationException.DuplicatedOutPoint
VerificationException.EmptyInputsOrOutputs
VerificationException.ExcessiveValue
VerificationException.LargerThanMaxBlockSize
VerificationException.NegativeValueOutput
VerificationException.NoncanonicalSignature
VerificationException.UnexpectedCoinbaseInput