Маленькая программа на Java выдаёт ошибку

[stiznt]

Я создаю маленькую программку, но при нажатии на кнопку у меня выводит ошибку.
вот
Класс Main

package ru.stiznt.Core;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

import javax.swing.JButton;
import javax.swing.JLabel;

public class Main {
	
	Listener list = new Listener();
	int h,mh,m,a;
	JButton b1, b2, b3, b4,jb1;
	JLabel l1, l2;
	Random r = new Random();
	String s1, s2;
	
	public void Window(){
		mh = 250;
		b1 = new JButton("Работа");
		b2 = new JButton("Отдых");
		b3 = new JButton("Счастье");
		b4 = new JButton("Магазин");
		l1 = new JLabel("Здоровье:"+h+"/"+mh);
		l2 = new JLabel("Деньги:"+m);
		
		b1.addActionListener(list);
		b2.addActionListener(list);
		b3.addActionListener(list);
		b4.addActionListener(list);
		
		
	}
	
	public void openWindowJob(){
		Job job = new Job("Работа");
		job.setSize(300, 200);
		job.setVisible(true);
	}
	
	public void job(){
		jb1 = new JButton("Рыскать по помойкам");
		
		jb1.addActionListener(list);
	}
	
	public class Listener implements ActionListener{

		
		
		public void actionPerformed(ActionEvent e) {
			if(e.getSource()==b1){
				openWindowJob();
			}
			if(e.getSource()==jb1){
				a = r.nextInt(5);
				h = h - 5;
				m = m+ a;
				s1 = "Здоровье:"+h+"/"+mh;
				s2 = "Деньги:"+m;
				l1.setText(s1);
				l2.setText(s2);
			}
			
		}
		
	}
}

Класс Job:

package ru.stiznt.Core;

import java.awt.FlowLayout;

import javax.swing.JFrame;

public class Job extends JFrame{
	Main main = new Main();
	public Job(String s){
		super(s);
		main.job();
		setLayout(new FlowLayout());
		
		
		
		add(main.jb1);
		
		
	}
}

Класс window:

package ru.stiznt.Core;


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




public class window extends JFrame{
	Main main  = new Main();
	
	public window(String s){
		super(s);
		setLayout(new FlowLayout());
		main.Window();
		
		add(main.l1);
		add(main.l2);
		add(main.b2);
		add(main.b3);
		add(main.b4);
		add(main.b1);
	}
}

И Класс Core:

package ru.stiznt.Core;

import javax.swing.JFrame;





public class Core {
	public static void main(String args[]){
		
		window w = new window("Тест");
		
		
		//Главное окно
		w.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		w.setResizable(false);
		w.setLocationRelativeTo(null);
		w.setSize(200, 125);
		w.setVisible(true);
		
		//Магазин
		
	}
}

Заранее спасибо)

_____
Код программы нужно выделять (форматировать) тегами [CODE] (читать FAQ)
Модератор

[WorldMaster]

Код оформите по правилам пожалста.
Что за ошибку то выводит?

[stiznt]

Сообщение от WorldMaster

Код оформите по правилам пожалста.
Что за ошибку то выводит?

Извиняюсь, что не оформил код.
Вот ошибка:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at ru.stiznt.Core.Main$Listener.actionPerformed(Main.java:63)
	at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
	at java.awt.Component.processMouseEvent(Unknown Source)
	at javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.awt.Component.processEvent(Unknown Source)
	at java.awt.Container.processEvent(Unknown Source)
	at java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.awt.Component.dispatchEvent(Unknown Source)
	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.awt.EventQueue.access$500(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.awt.EventQueue$3.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue$4.run(Unknown Source)
	at java.awt.EventQueue$4.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)

[WorldMaster]

Проверьте код вот тут в отладчике:

if(e.getSource()==b1){
				openWindowJob();
			}
			if(e.getSource()==jb1){
				a = r.nextInt(5);
				h = h - 5;
				m = m+ a;
				s1 = "Здоровье:"+h+"/"+mh;
				s2 = "Деньги:"+m;
				l1.setText(s1);
				l2.setText(s2);
			}

Наверное e равна null
Либо дальше в обработчике встречается недействительная ссылка.