Login & Registration Form

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class GUI extends JFrame implements ActionListener{
    //Frame Login
    JButton signIn=new JButton("Log In");
    JButton signUp=new JButton("Register");
    JTextField id=new JTextField();
    JPasswordField pass=new JPasswordField();
    JPanel grid=new JPanel(new GridLayout(4,2,0,10));
    Font x=new Font("SansSerif",Font.BOLD, 36);
    JLabel loginStatus=new JLabel("Selamat Datang . . . . .");
    int flag=1;

    //Frame Regis
    JFrame R=new JFrame("Registrasi");
    JPanel data=new JPanel(new GridLayout(3,2));
    JPanel doneStatus=new JPanel(new GridLayout(3,1));
    JPanel bawah=new JPanel(new GridLayout(1,2));
    JPanel box=new JPanel(new GridLayout(3,1));
    JTextField rId=new JTextField();
    JPasswordField rPass=new JPasswordField();
    JPasswordField rPass2=new JPasswordField();
    JLabel statid=new JLabel();
    JLabel pass1=new JLabel();
    JLabel pass2=new JLabel();
    JButton done = new JButton("Done");

    //Data Base
    String[] username =new String[50];
    String[] password =new String[50];
    int jumlah=0;

    GUI(){
        component();
        frame();
    }

    void frame(){
        setLayout(new FlowLayout(FlowLayout.CENTER,20,20));
        setTitle("Login");
        setSize(500,400);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        setResizable(false);
    }

    void component(){
         grid.add(new JLabel("Username"));
         grid.add(id);
         grid.add(new JLabel("Password"));
         grid.add(pass);
         grid.add(loginStatus);
         grid.add(new JLabel());
         grid.add(signIn);signIn.addActionListener(this);
         grid.add(signUp);signUp.addActionListener(this);
         add(grid);
    }

    public static void main(String[] args) {
        new GUI();
    }

    public void actionPerformed(ActionEvent e) {
        System.out.println(e.getActionCommand()+validasi());
        if (e.getActionCommand().equals("Log In")) {
            flag=0;
            for (int i = 0; i < jumlah; i++) {
                if(username[i].equals(id.getText())&&password[i].equals(pass.getText())){
                    flag=1;
                    suksesLogin();
                    break;
                }
            }
            if (flag!=1)
                loginStatus.setText("Data Tidak ditemukan");
        }
        else if(e.getActionCommand().equals("Register")){
            regis();
        }
        else if(e.getActionCommand().equals("Done")&&validasi()==3){
            username[jumlah]=rId.getText();
            password[jumlah]=rPass.getText();
            jumlah++;
            R.setVisible(false);
            setVisible(true);
        }
    }

    void suksesLogin(){
        JFrame sukses=new JFrame("Home");
        JLabel y=new JLabel("Sukses Login");
        y.setFont(x);
        sukses.add(y,BorderLayout.CENTER);
        sukses.setVisible(true);
        setVisible(false);
        sukses.setSize(300,200);
        sukses.setLocationRelativeTo(null);
        sukses.setDefaultCloseOperation(EXIT_ON_CLOSE);
        sukses.setResizable(false);
    }

    void regis(){
        R.setVisible(true);
        R.setLayout(new FlowLayout(FlowLayout.CENTER,50,50));
        setVisible(false);
        R.setSize(500,400);
        R.setLocationRelativeTo(null);
        R.setDefaultCloseOperation(EXIT_ON_CLOSE);
        R.setResizable(false);
        data.add(new JLabel("Username"));
        data.add(rId);
        data.add(new JLabel("Password"));
        data.add(rPass);
        data.add(new JLabel("Ulang Password"));
        data.add(rPass2);
        JLabel y=new JLabel("Form Registrasi");
        y.setFont(x);
        box.add(y);
        box.add(data);
        doneStatus.add(statid);
        doneStatus.add(pass1);
        doneStatus.add(pass2);
        bawah.add(doneStatus);
        bawah.add(done);done.addActionListener(this);
        box.add(bawah);
        R.add(box);
        reset();
    }

    void reset(){
        rId.setText("");
        rPass.setText("");
        rPass2.setText("");
        id.setText("");
        pass.setText("");
    }

    int validasi(){
        flag=0;
        if(rPass.getText().equals(rPass2.getText()))
            flag++;
        else
            pass2.setText("Password berbeda");
        if(rId.getText().length()>=5&&rId.getText().length()<=10)
            flag++;
        else
            statid.setText("Id [5...10]");
        if(rPass.getText().length()>=5&&rPass.getText().length()<=15)
            flag++;
        else
            pass1.setText("Password [5....15]");
        System.out.println(flag);
        return flag;
    }
}