Answer Posted / dinesh

Connection pooling whic h use to Reuse the Connection
resource.To Avoid wastage of connection resources,So you
don't need to have new connection ,Instead of creating new
connection,You can use the connection from connection pool
resource
A database driver may contain a connection pool as part of
its services, through its implementation of the
javax.sql.DataSource interface. DataSource objects are used
with JNDI.

With example:
import java.sql.*;
import java.util.*;
import org.w3c.dom.*;
import DBConnectionManager;

public class XSQL {
static DBBroker pool = DBBroker.getInstance();
// <---- Pool code!

public static Element executeQuery(
String connectionName,
String statementId,
String statementText,
Document factory
)
throws SQLException
{
Connection connection = null;
DBConnection db = null;
// <---- Pool code!
try {
db = pool.getConnection(connectionName);
// <---- Pool code!
connection = db.getConnection();
// <---- Pool code!
Statement statement = connection.createStatement();
ResultSet resultSet =
statement.executeQuery(statementText);
ResultSetMetaData metaData = resultSet.getMetaData();
int columnCount = metaData.getColumnCount();

Element rowSet = factory.createElement("xsql:rowset");
rowSet.setAttribute("id", statementId);

for (int i = 0; resultSet.next(); i++) {
Element row = factory.createElement("xsql:row");
row.setAttribute("sequence", String.valueOf(i + 1));
rowSet.appendChild(row);

for (int j = 0; j &lt; columnCount; j++) {
String value = resultSet.getString(j + 1);

Element element = factory.createElement(
metaData.getColumnLabel(j + 1).toLowerCase()
);
row.appendChild(element);

if (value != null) {
element.appendChild(
factory.createTextNode(value)
);
}
}
}

resultSet.close();
statement.close();

return rowSet;
} catch (SQLException e) {
throw(new SQLException(statementText));
} finally {
if (connection != null) {
pool.releaseConnection(db); // <---- Pool code!
}
}
}

}
If u r not understand the code,If ur the beginners that
prespective to
http://publib.boulder.ibm.com/infocenter/iseries/v5r3/index.jsp?topic=/rzaha/poolnods.htm

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