To create a JDBC resource, specify the connection pool with which it is associated. Multiple JDBC resources can specify a single connection pool.
A JDBC connection pool is a group of reusable connections for a particular database. Because creating each new physical connection is time consuming, the server maintains a pool of available connections to increase performance. When an application requests a connection, it obtains one from the pool. When an application closes a connection, the connection is returned to the pool.
The properties of connection pools can vary with different database vendors. Some common properties are the database’s name (URL), user name, and password.