Creating a Simple Application:
Before running this program, you need a pre-created table in the database. You can also create a table using JDBC. Just i said, creating a JDBC Application is a methodical job. Mainly in all the (or in 90%) JDBC program, you need to follow these following 6 steps.
  • Import the packages — requires that you include the packages containing the JDBC classes needed for database programming. Most often, using import java.sql.* will suffice.
  • Register the JDBC driver — requires that you initialize a driver so you can open a communications channel with the database.
  • Open a connection — Requires using the DriverManager.getConnection() method to create a Connection object, which represents a physical connection with the database.
  • Execute a Query — requires using an object of type Statement for building and submitting an SQL statement to the database.
  • Extract data from result set — Requires that you use the appropriate ResultSet.getXXX() method to retrieve the data from the result set.
  • Clean up the environment — Requires explicitly closing all database resources versus relying on the JVM’s garbage collection.
   Sample Example  Steps:
    1. Import the packages :
        Before you can create a java jdbc connection to the database, you must first import the
    java.sql package.
    import java.sql.*; The star ( * ) indicates that all of the classes in the package java.sql are to be imported.
    2. Register the JDBC driver:
     In this step of the jdbc connection process, we load the driver class by calling Class.forName() with the Driver     class name as an argument. Once loaded, the Driver class creates an instance of itself. A client can connect to Database Server through JDBC Driver. Since most of the Database servers support ODBC driver therefore JDBC-ODBC Bridge driver is commonly used.
The return type of the Class.forName (String ClassName) method is “Class”. Class is a class in
java.lang package.

try {
Class.forName(”sun.jdbc.odbc.JdbcOdbcDriver”); //Or any other driver }
 catch(Exception x){ System.out.println( “Unable to load the driver class!” ); }
3. Open a connection:
    The JDBC DriverManager class defines objects which can connect Java applications to a JDBC driver. DriverManager is considered the backbone of JDBC architecture. DriverManager class manages the JDBC drivers that are installed on the system. Its getConnection() method is used to establish a connection to a database. It uses a username, password, and a jdbc url to establish a connection to the database and returns a connection object. A jdbc Connection represents a session/connection with a specific database. Within the context of a Connection, SQL, PL/SQL statements are executed and results are returned. An application can have one or more connections with a single database, or it can have many connections with different databases. A Connection object provides metadata i.e. information about the database, tables, and fields. It also contains methods to deal with transactions.

JDBC URL Syntax: 
    jdbc: <subprotocol>: <subname>
JDBC URL Example:
 jdbc: <subprotocol>: <subname>
•Each driver has its own subprotocol
•Each subprotocol has its own syntax for the source. We’re using the jdbc odbc subprotocol, so the DriverManager knows to use the sun.jdbc.odbc.JdbcOdbcDriver.
try{
Connection dbConnection=DriverManager.getConnection(url,”loginName”,”Password”);
} catch( SQLException x ){
System.out.println( “Couldn’t get connection!” );
}
4. Execute a Query:
    Once a connection is obtained we can interact with the database. Connection interface defines methods for interacting with the database via the established connection. To execute SQL statements, you need to instantiate a Statement object from your connection object by using the createStatement() method.

Statement statement = dbConnection.createStatement();
A statement object is used to send and execute SQL statements to a database.
Three kinds of Statements

Statement:
Execute simple sql queries without parameters.
Statement createStatement()
Creates an SQL Statement object.

Prepared Statement:
Execute precompiled sql queries with or without parameters.
PreparedStatement prepareStatement(String sql)
returns a new PreparedStatement object. PreparedStatement objects are precompiled
SQL statements.

Callable Statement:
Execute a call to a database stored procedure.
CallableStatement prepareCall(String sql)
returns a new CallableStatement object. CallableStatement objects are SQL stored procedure call statements.