Problem with JRadioButton and ButtonGroup - Identifier Expected error?

[hypernova]

Hi guys, I'm new to Java and this is probably a really silly question, or at least is has a simple answer because I don't understand something, most probably...

Here is the contents of the file "OrderFrame":

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

public class OrderFrame extends JFrame{

	private JPanel BaseSelectPanel, SizeSelectPanel, ExtraSelectPanel,
		ToppingSelectPanel, NumberSelectPanel, PizzaPricePanel,
		DeliverySelectPanel, OrderSummaryPanel;

	private class BasePanel extends JPanel{
		private JPanel BaseSelectPanel = new JPanel();
		private JLabel BaseSelectLabel = new JLabel("Base type:");
		private JRadioButton ItalianButton = new JRadioButton("Italian", true);
		private JRadioButton PanButton = new JRadioButton("Pan", false);
		private ButtonGroup RadioGroup = new ButtonGroup();
		RadioGroup.add(ItalianButton);       //Identifier expected?
		RadioGroup.add(PanButton);          //Identifier expected?
		BasePanel.add(BaseSelectLabel);   //Identifier expected?
		BasePanel.add(ItalianButton);       //Identifier expected?
		BasePanel.add(PanButton);           //Identifier expected?
                                                               //I find that this.add does not work either, which one should I be using?
	}

	public OrderFrame(){
		super("Pizza Hut UK Order Form");
		this.setLayout(new FlowLayout());
		this.setSize(800,600);
		BasePanel basepanel = new BasePanel();
		add(basepanel);


	}
}

The error lines are commented. What am I doing wrong?
Another thing I have found is that I have seen 'this.add' and '<name>.add' used... What does the 'this.' keyword do?

[camickr]

First of all use standard Java naming conventions. Variable names DO NOT start with an upper case character.

"RadioGroup" should be "radioGroup" etc...

You need to create a constructor for your BasePanel class. Then all the add(...) statements need to be moved to the constructor.

[hypernova]

So lines 25 through 30 are not a constructor? What is meant by a constructor? I "googled" and found that 'a constructor is like a method, but not exactly like a method', and it creates a new instance of a class, but what does this mean and how do I use one?

[Tolls]

If you don't know what constructors are then i woudl suggest stepping away from Swing and learn the basics.
Start here, with the basics, specifically this section.

[hypernova]

Yep I've read most of that today. I already know roughly what a class is and why oop is used from programming in C++, but all this nesting of things is tricky concept.

[camickr]

public OrderFrame() is a constructor for your OrderFrame class.

Now you need a public BasePanel() for the BasePanel class.

[hypernova]

Ah right! I think I understand, thanks.