user3014: Using the daemon and not a 3rd party pinging service, what is the best way to get notified of new payments?
Do we need to constantly poll the server?

user153: Bitcoin New transactions can be discovered by polling using the listsinceblock API command with the Bitcoin.org client.
Beginning with v0.8.2 of the Bitcoin-Qt/bitcoind client is -walletnotify option that can run a process when a transaction that affects the wallet is seen.
The BitsOfProof supernode will offer this as well I believe.
[Update: Thanks to Pelle's answer to a related question,
You can do this using BitcoinJ by implementing the PeerEventListener interface.
The OnTransaction will be called every time a new Transaction is broadcast out and received from a Peer ]

3014: <p>Using the daemon and not a 3rd party pinging service, what is the best way to get notified of new payments?
Do we need to constantly poll the server?</p>
 153: <p>Bitcoin New transactions can be discovered by polling using the listsinceblock API command with the Bitcoin.org client.</p>

<p>Beginning with v0.8.2 of the Bitcoin-Qt/bitcoind client is -walletnotify option that can run a process when a transaction that affects the wallet is seen.</p>

<p>The BitsOfProof supernode will offer this as well I believe.</p>

<p>[Update: Thanks to <a href="https://bitcoin.stackexchange.com/a/8133/153">Pelle's answer</a> to a related question,</p>

<p>You can do this using BitcoinJ by implementing the <a href="http://code.google.com/p/bitcoinj/source/browse/core/src/main/java/com/google/bitcoin/core/PeerEventListener.java" rel="nofollow noreferrer">PeerEventListener</a> interface.</p>

<p>The <a href="http://code.google.com/p/bitcoinj/source/browse/core/src/main/java/com/google/bitcoin/core/PeerEventListener.java#74" rel="nofollow noreferrer">OnTransaction</a> will be called every time a new Transaction is broadcast out and received from a Peer ]</p>
