5. Extract data from result set:
     Statement interface defines methods that are used to interact with database via the execution of SQL statements. The Statement class has three methods for executing statements:
executeQuery(), executeUpdate(), and execute(). For a SELECT statement, the method to use is executeQuery . For statements that create or modify tables, the method to use is executeUpdate. Note: Statements that create a table, alter a table, or drop a table are all examples of DDL
statements and are executed with the method executeUpdate. execute() executes an SQL
statement that is written as String object.
ResultSet provides access to a table of data generated by executing a Statement. The table rows are retrieved in sequence. A ResultSet maintains a cursor pointing to its current row of data. The next() method is used to successively step through the rows of the tabular results.
ResultSetMetaData Interface holds information on the types and properties of the columns in a ResultSet. It is constructed from the Connection object.
6. Clean up the environment:
    Closing database connection 
           try{
                // code
            }finally{
            connection.close();
            }
Sample Example:
Pre-Requisite: 
    You need to have good understanding on the following two subjects to learn JDBC:
  1. Core JAVA Programming
  2. SQL or MYSQL Database
JDBC - Environment Setup: 
    Make sure you have done following setup:
  1. Core JAVA Installation
  2. SQL or MySQL Database Installation
Apart from the above you need to setup a database which you would use for your project. Assuming this is EMP and you have created on table Employees within the same database.
//STEP 1. Import required packages
import java.sql.*;
public class FirstExample { 
    // JDBC driver name and database URL 
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; 
    static final String DB_URL = "jdbc:mysql://localhost/EMP"; 
    // Database credentials 
    static final String USER = "username"; 
    static final String PASS = "password"; 
    public static void main(String[] args) { 
        Connection conn = null; 
        Statement stmt = null; 
        try{ 
                //STEP 2: Register JDBC driver 
                Class.forName("com.mysql.jdbc.Driver");
                 //STEP 3: Open a connection 
                System.out.println("Connecting to database..."); 
                conn = DriverManager.getConnection(DB_URL,USER,PASS); 
                 //STEP 4: Execute a query 
                System.out.println("Creating statement...");
                stmt = conn.createStatement(); 
                String sql; sql = "SELECT id, first, last, age FROM Employees"; 
                ResultSet rs = stmt.executeQuery(sql); 
                //STEP 5: Extract data from result set 
                while(rs.next()){ 
                    //Retrieve by column name
                     int id = rs.getInt("id"); 
                     int age = rs.getInt("age"); 
                     String first = rs.getString("first"); 
                     String last = rs.getString("last"); 
                    //Display values 
                    System.out.print("ID: " + id); 
                    System.out.print(", Age: " + age); 
                    System.out.print(", First: " + first); 
                    System.out.println(", Last: " + last);
                 }