Winter '10 introduces a new Bulk API that is optimized to insert, update, or upsert a large number of records asynchronously. The new Bulk API allows you to load large batches of data that are processed in the background. The Bulk API offers a number of benefits over loading data with the regular SOAP-based Web Services API:

• You can load data faster because of parallel processing and fewer network round-trips.
• You can monitor currently processing and completed data loads, and abort current data loads.
• You can enjoy improved robustness as large data loads complete quicker and are less likely to be disrupted by network failures.

Java developers who want to write Bulk API clients can take advantage of the open source Web Service Connector toolkit maintained by salesforce.com. Because the Bulk API follows REST principles, it is straightforward to write clients on a variety of platforms and in many programming languages. The Bulk API Developer's Guide shows you how to build Bulk API clients.