请教这段代码有什么有关问题?为什么在浏览器中运行的时候提示"java lang nullpointerException"

请问这段代码有什么问题?为什么在浏览器中运行的时候提示"java lang nullpointerException"
import   java.awt.*;
import   java.applet.*;
import   java.awt.event.*;

class   NamePanel   extends   Panel
{
Label   name;TextField   text;
NamePanel()
{
name=new   Label( "姓名 ");
text=new   TextField(10);
setLayout(new   GridLayout(1,2));
add(name);add(text);  
}
}
class   SexPanel   extends   Panel
{
Label   xingbie;
Checkbox   female,male;
CheckboxGroup   sex;
GridLayout   a=new   GridLayout(1,2);
Panel   p1=new   Panel();
SexPanel()
{
this.setLayout(a);
sex=new   CheckboxGroup();
xingbie=new   Label( "性别 ");
female=new   Checkbox( "女 ",true,sex);
male=new   Checkbox( "男 ",false,sex);
p1.add(female);p1.add(male);
add(xingbie);add(p1);
}
}
class   Interest   extends   Panel
{
Label   interests;
Checkbox   box1,box2,box3,box4;
GridLayout   b=new   GridLayout(1,2);
Panel   p2=new   Panel();
Interest()
{
setLayout(b);
interests=   new   Label( "爱好 ");
box1=new   Checkbox( "体育 ");box2=new   Checkbox( "游戏 ");
box3=new   Checkbox( "唱歌 ");box4=new   Checkbox( "跳舞 ");
p2.add(box1);p2.add(box2);p2.add(box3);p2.add(box4);
add(interests);
add(p2);
}
}
class   All   extends   Panel  
{
Button   submit,reset;
NamePanel   allname;
SexPanel   allsex;
Interest   allinterest;
GridLayout   c=new   GridLayout(4,1);
Panel   p=new   Panel();
All()
{
setLayout(c);
p.add(submit);p.add(reset);
allname=new   NamePanel();
allsex=new   SexPanel();
allinterest=new   Interest();
add(allname);add(allsex);add(allinterest);add(p);
}
}
public   class   Mytest   extends   Applet   implements   ActionListener
{
All   test;
Label   success;
CardLayout   card;
public   void   init()
{
card=new   CardLayout();
setLayout(card);
test=new   All();
add( " ",test);
success=new   Label( "成功发送 ");
add( " ",success);
test.submit.addActionListener(this);
test.reset.addActionListener(this);
}
public   void   actionPerformed(ActionEvent   e)
{
if(e.getSource()==test.submit)
{
card.last(this);
}
else   if(e.getSource()==test.reset)
{
test.allname.text.setText(null);
test.allsex.female.setState(false);
test.allsex.male.setState(false);
test.allinterest.box1.setState(false);
test.allinterest.box2.setState(false);
test.allinterest.box3.setState(false);
test.allinterest.box4.setState(false);
}
}
}

编译之后我用 <applet   code= "Mytest.java "   height=300   width=300   />
运行时候在浏览器里面就提示这个java   lang   nullpointerException
错在哪里呢?

------解决方案--------------------
你添加的按扭没有实例化
------解决方案--------------------
Button submit,reset;
======================================
在什么地方new的？