Exception hierarchy enabling sophisticated error handling independent of the data access approach in use. For example, when DAOs and data access frameworks use the exceptions in this package (and custom subclasses), calling code can detect and handle common problems such as deadlocks without being tied to a particular data access strategy, such as JDBC.

All these exceptions are unchecked, meaning that calling code can leave them uncaught and treat all data access exceptions as fatal.

The classes in this package are discussed in Chapter 9 of Expert One-On-One J2EE Design and Development by Rod Johnson (Wrox, 2002).