Q)What is the limitation of DriverManager?
       =>DriverManager is a connection factory. I.e. it provides
       database connections to Java components.
       =>DriverManager has the following limitations.

           1)performance compromise in providing the database
	   connection.

	   2)connections are not reusable and there by not cost-effective.

	   3)Connection acquring code is not secure.

	   4)Doesn't support distributed transactions.

Note:- In realtime Java projects,   javax.sql.DataSource is used
as connection factory. It addresses all the limitations
of DriverManager.
Q)What is a connection pool?
   =>A group of (collection of) pre-created database   connections kept in cache for use and reuse is   nothing but a connection pool.

Q)What is connection pooling?
    =>The mechanism  of creating  the connection    pool  and providing  pooled connections     to application components  is nothing but  connection pooling.

  DIAGRAM
Once the Container(Tomcat/Weblogic/Web Sphere/JBoss) administrator
configures the connection pool, Connection pool is created.

=>Object Oriented representation of connection pool is nothing but javax.sql.DataSource object. DataSource object is registered with naming service with some name that runs within the server.

=>Java component that needs a pooled connection should perform the following
things.
   1)Connect to the naming service.

             InitialContext ic=new InitialContext();


       Perform lookup for DataSource object.
                    DataSource ds=(DataSource)ic.lookup("myds");

   2)  Connection connection=ds.getConnection();