Выдает ошибку java.lang.NullPointerException

Question

код`package test;

import javax.swing.JButton;
import javax.swing.JTextField;


public class Test {

    private JButton b;
    private JTextField t;
    private MyFrame f;


    public static void main(String[] args) {

        Test test = new Test();
        test.bb();
        test.tt();
        test.ff();

    }

    private  void bb(){
        b=new JButton("{ff");
        ab();

    }

    private void tt(){
        t = new JTextField(10);
    }

    private void ff(){
        f=new MyFrame("ee", 130, 100);
        f.add(t);
        f.add(b);
    }

    private void ab(){
        Lis l = new Lis(b,t);
        b.addActionListener(l);
    }

}

    package test;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JTextField;


public class Lis implements ActionListener{

    private JButton b;
    private JTextField t;



    public Lis (JButton bb, JTextField tt){
        b=bb;
        t=tt;
    }


    @Override
    public void actionPerformed(ActionEvent e) {

        if(e.getSource() == b){
            System.out.println(t.getText());
            }
    }

}
    package test;

import java.awt.FlowLayout;
import javax.swing.JFrame;


public class MyFrame extends JFrame{

     public MyFrame(String title, int wigth, int higth ){
       super.setTitle(title);
        super.setSize(wigth, higth);
        super.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        super.setLayout(new FlowLayout());
        super.setLocationRelativeTo(null);
        super.setVisible(true);

    }

}

Answer 1

 public static JTextField t; //Замените на статик 
    if(e.getSource() == b){
        System.out.println(Test.t.getText());//Обратитесь так 
    }