Harikrishna,<br/>
The data you provided is partly incomplete. I am giving the solution considering you have Oracle in your system. If you have any other DB, check the
Connection and Drivermanager parts.<br/><br/>

The answer contains 2 parts<br/>
1. Registering the user<br/>
- Create a table in the Database to store user details<br/>
- Put some Signup screen and ask user to enter details along with desired user name and password<br/>
- On submit, send the data to a Jsp or servlet (preferable).<br/>
- Do a primary validation, like empty values and special charecters etc, on the data entered.<br/>
- Using JDBC create a connection and store the values in the database<br/><br/>

2. Validating the login<br/>
- After submitting the User ID and Password in the login page, forward the control to a jsp or servlet(preferable).<br/>
- Do a primary validation, like empty values and special charecters etc, on the data entered.<br/>
- Using JDBC create a connection<br/>
- Create a Statement/ PreparedStatement object and send the connection object as parameter.<br/>
- Create a Resultset object<br/>
- Execute the query to retrive the user details for given User ID, and store the values in the Resultset Object<br/>
- Validate the resultset and content and check for the data in the Password column with the password given by the user<br/><br/>

================================================<br/>
Here I am putting some sample code.<br/>
Send user id and password as commanline arguments.<br/>
Create a table "usermaster" in oracle with uid, pwd, username as columns.<br/>
I just wrote this code on flow. I even't compile this code. This is just to give an idea to you.
Hapy Programming ;-)
================================================<br/>
import java.sql.*

public class JDBCSample {

public static void main( String args[]) {

static String userid=?scott?, password = ?tiger?;
String connectionURL = "jdbc:odbc:test";
// Change the connection string according to your db, ip, username and password

Connection dbConnection = null;
Statement statement = null;
ResultSet rs = null;

try {
// Load the Driver class.
Class.forName(?sun.jdbc.odbc.JdbcOdbcDriver?); //Or any other driver

// If you are using any other database then load the right driver here. For example, for PostgreSQL, Class.forName("org.postgresql.Driver");

//Create the connection using the static getConnection method
dbConnection=DriverManager.getConnection(connectionURL,userid,password)

//Create a Statement class to execute the SQL statement
statement = dbConnection.createStatement();

//Execute the SQL statement and get the results in a Resultset
rs = statement.executeQuery("select username from usermaster where uid='"+args[0]+"' and password='"+args[1]+"'");
//To insert data use the following code
// rs = statement.executeUpdate("insert into usermaster set uid='"+args[0]+"' and password='"+args[1]+"', username='" +args[2]+"'");

// Check the ResultSet for values
if(rs.next()) {
// fetch the row data using the getString method
System.out.println("Welcome " + rs.getString("username"));
} else {
System.out.println("Invalid UserID/Password ");
}
}
catch (SQLException sqle) {
sqle.printStackTrace();
}
catch (Exception ex) {
e.printStackTrace();
}
finally {
// Close the connection
try{
dbConnection.close();
rs.close();
}
exception(Exception ex){
ex.printStackTrace();
}
}
}
}