Null pointer exception

[tnrh1]

Hello.
I'm trying to add to my JLabel array list a JLabel and I'm getting a null pointer exception.
Here is a piece of my code:

import java.applet.Applet;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.util.ArrayList;

import javax.swing.*;


public class Calculate extends Applet
{
	private ArrayList<JLabel>label;
	private ArrayList<JButton>button;
	private ArrayList<JTextField>tfield;
	private GridBagConstraints c;
	
	public void init()
	{
		setLayout(new GridBagLayout());
		c = new GridBagConstraints(); 
		label.add(new JLabel("Your weight:"));
		c.gridx = 0;
		c.gridy = 0;
		add(label.get(0),c);
		
            } 

}

The exception happens in this line:

label.add(new JLabel("Your weight:"));

java.lang.NullPointerException
at Calculate.init(Calculate.java:20)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

I know it's an applet but it's more a java syntax/coding question.

Thanks in advanced.

[tnrh1]

That was such a stupid mistake I just noticed you may delete the thread if you want.
I didn't initalize the ArrayList.