How Do I Run A Class From Another Class?

Question

Hiya everyone, id like to know how to run a class from another class.
Ive got a Login class which extends a JFrame and a Personnel class which also extends a JFrame. When i press the login button (in Login class), ive got it to decide if password/login are acceptable and if they are, I want the Login class to close then run the Personnel class.
Im just after the code which says to close this class and run the Personnel class. How do i do that?
Ive researched this but couldnt get an understandable answer!
Help would be much appreciated, Ant...

Answer 1

This is the Login Class:
public class MainMenu extends javax.swing.JFrame {
    Statement statement = null;
    int currentRecord;
    ResultSet rs = null;
    String name = null, job = null, mission = null, login = null, password = null;
    String loginVal;
    String passwordVal;
    /** Creates new form MainMenu */
    public MainMenu() {
        initComponents();
        try{
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
            String filename = System.getProperty("user.dir") + "/src/Personnel.mdb";
            String database = "jdbc:odbc:Driver={Microsoft Access Driver (*.mdb)};DBQ=" + filename;
            Connection conn = DriverManager.getConnection( database , "","");
            statement = conn.createStatement();
            System.out.println("Connected...ok");
        } catch (Exception e) {
            System.err.println("Got a connection Problem!");
            System.err.println(e.getMessage());
    private void btnLoginActionPerformed(java.awt.event.ActionEvent evt) {                                        
        loginVal = txtLogin.getText();
        passwordVal = txtPassword.getText();
        String name = null, job = null, mission = null, login = null, password = null;
        try{
            rs = statement.executeQuery("SELECT Login,Password FROM Personnel WHERE Login = '" + loginVal + "' ");
            System.out.println("TRYING SELECT CLAUSE");
            if(rs.next()){
                System.out.println("THERE IS A NEXT RECORD");
                login = rs.getString(1);
                password = rs.getString(2);
                System.out.println("GOT THE NEXT RECORD");
                System.out.println(login + password);
            System.out.println("Query Complete");
        }catch(Exception s){
            //s.printStackTrace();
            System.out.println("NO RECORDS EXIST FOR THIS LOGIN ID");
        if(passwordVal.equals(password)){
            System.out.println("Access Granted"); //CLOSE MAIN AND RUN CONTROL CLASS
        } else{
            System.out.println("Access Denied"); //RE-RUN CLASS
    }