In late 2009, Tomcat developers decided to wait until Tomcat 7 to implement forthcoming updates to the commons database connection pooling library DBCP designed to implement JDBC 4 support.
While DBCP 1.4, which offers this support, will still not be implemented until Tomcat 7's release in late summer 2010, Tomcat developers are now considering including DBCP 1.3 in Tomcat 6.0.27, the next version of the Tomcat 6 branch, which is expected for release in the near future.
DBCP 1.3, which was released in February of 2010, implements the same major changes and updates as DBCP, but does not include any of the JDBC 4 support features.
Improvements to the library include semantics updates for clarity, clarified JavaDocs for a number of methods, a new validationQueryTimeout parameter for more fine-grained validation control, support for XA interface configuration via a new XADataSource object, and changes to the connection closing behavior of Connection, Statement, PreparedStatement, CallableStatement, and ResultSet in compliance with their respective JavaDoc.
Also new in DBCP 1.3, the SQLNestedException element has been deprecated in favor of SQLException, in preparation for the implementation of standard Java exception chaining in DBCP 2.0.
Although at this time, there has been no further talk of implementing JDBC 4 in Tomcat 6, previous discussion indicates that users requiring support for version 4, which is optimized for use with JDK 1.6, will be able to download the Tomcat 7 DBCP libraries and use them with Tomcat 6.
For more information about the changes to Commons-DBCP, visit the project website.