“Connection Pool”
Connection Pool is the cache of a database, which maintain the connection when we reused future requests. Generally, it is used for increasing the performance of executing commands on a database.
In connection pooling, when the connection is created, it is placed in the pool and reused again before establishing new connections.
"Connection Pool Architecture"

JDBC Connection Pooling Scope:
import java.sql.*;
public class JDBCServlet extends HttpServlet {
private Connection connection;
public void init(ServletConfig c) throws ServletException {
……………..
…………….. // write some code for Open the connection
………………….
}
public void destroy() {
………………………..
…………………. //write some code for Close the connection
}
public void doGet (HttpServletRequest req, HttpServletResponse res) throws ServletException {
……………..
………….. //Use the connection here
Statement stmt = connection.createStatement();
…………………..
…………………. // perform JDBC Work
…………………
}
}