Description:

Many Jakarta projects support interaction with a relational database. Creating
a new connection for each user can be time consuming (often requiring multiple
seconds of clock time), in order to perform a database transaction that might
take milliseconds.
Opening a connection per user can be unfeasible in a publicly-hosted Internet
application where the number of simultaneous users can be very large.
Accordingly, developers often wish to share a "pool" of open connections
between all of the application's current users. The number of users actually
performing a request at any given time is usually a very small percentage of
the total number of active users, and during request processing is the only
time that a database connection is required.
The application itself logs into the DBMS, and handles any user account issues
internally.
There are several Database Connection Pools already available, both within
Jakarta products and elsewhere. This Commons package provides an opportunity
to coordinate the efforts required to create and maintain an efficient,
feature-rich package under the ASF license.
The commons-dbcp package relies on code in the commons-pool package to provide
the underlying object pool mechanisms that it utilizes.
Applications can use the commons-dbcp component directly or through the
existing interface of their container / supporting framework.
For example the Tomcat servlet container presents a DBCP DataSource as a JNDI
Datasource. James (Java Apache Mail Enterprise Server) has integrated DBCP
into the Avalon framework. A Avalon-style datasource is created by wrapping
the DBCP implementation. The pooling logic of DBCP and the configuration found
in Avalon's excalibur code is what was needed to create an integrated reliable
DataSource.