How to generate a Auto key in jdbc Program

Program:

public class AutoGenKeys {

    public static void main(String args[]) {

        String url = "jdbc:mySubprotocol:myDataSource";

Connection con = null;
PreparedStatement pstmt;
String insert = "INSERT INTO COFFEES VALUES ('HYPER_BLEND', " +
"101, 10.99, 0, 0)";
String update = "UPDATE COFFEES SET PRICE = ? WHERE KEY = ?";

try {

Class.forName("myDriver.ClassName");

} catch(java.lang.ClassNotFoundException e) {
        System.err.print("ClassNotFoundException: ");
    System.err.println(e.getMessage());
}

try {

     con = DriverManager.getConnection(url,
"myLogin", "myPassword");

pstmt = con.prepareStatement(insert,
Statement.RETURN_GENERATED_KEYS);

pstmt.executeUpdate();
ResultSet keys = pstmt.getGeneratedKeys();

int count = 0;

keys.next();
int key = keys.getInt(1);

pstmt = con.prepareStatement(update);
pstmt.setFloat(1, 11.99f);
pstmt.setInt(2, key);
pstmt.executeUpdate();

keys.close();
pstmt.close();
      con.close();

} catch (SQLException e) {
     e.printStackTrace();
}

    }

}