Forest fire/Java/Graphics

The processing and underlying forest encoding works the same as the text version, but the output is to a JPanel instead.

import java.awt.Color;
import java.awt.Graphics;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Fire extends JFrame{
	private static final char BURNING = 'w'; //w looks like fire, right?
	private static final char TREE = 'T';
	private static final char EMPTY = '.';
	private static final double F = 0.02;
	private static final double P = 0.01;
	private static final double TREE_PROB = 0.5;
	private List<String> land;
	private JPanel landPanel;
	
	public Fire(List<String> land){
		this.land = land;
		landPanel = new JPanel(){
			@Override
			public void paint(Graphics g) {
				for(int y = 0; y < Fire.this.land.size();y++){
					String row = Fire.this.land.get(y);
					for(int x = 0; x < row.length();x++){
						switch(row.charAt(x)){
							case BURNING:
								g.setColor(Color.RED);
								break;
							case TREE:
								g.setColor(Color.GREEN);
								break;
							default: //will catch EMPTY
								g.setColor(Color.WHITE);
						}
						g.fillRect(x*3, y*3, 3, 3);
					}
				}
			}
		};
		//each block in the land is a 3x3 square
		landPanel.setSize(this.land.get(0).length() * 3, this.land.size() * 3);
		add(landPanel);
		setSize(200, 200);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
	}
	
	private List<String> process(List<String> land){
		List<String> newLand = new LinkedList<String>();
		for(int i = 0; i < land.size(); i++){
			String rowAbove, thisRow = land.get(i), rowBelow;
			if(i == 0){//first row
				rowAbove = null;
				rowBelow = land.get(i + 1);
			}else if(i == land.size() - 1){//last row
				rowBelow = null;
				rowAbove = land.get(i - 1);
			}else{//middle
				rowBelow = land.get(i + 1);
				rowAbove = land.get(i - 1);
			}
			newLand.add(processRows(rowAbove, thisRow, rowBelow));
		}
		return newLand;
	}

	private String processRows(String rowAbove, String thisRow,
			String rowBelow){
		String newRow = "";
		for(int i = 0; i < thisRow.length();i++){
			switch(thisRow.charAt(i)){
			case BURNING:
				newRow+= EMPTY;
				break;
			case EMPTY:
				newRow+= Math.random() < P ? TREE : EMPTY;
				break;
			case TREE:
				String neighbors = "";
				if(i == 0){//first char
					neighbors+= rowAbove == null ? "" : rowAbove.substring(i, i + 2);
					neighbors+= thisRow.charAt(i + 1);
					neighbors+= rowBelow == null ? "" : rowBelow.substring(i, i + 2);
					if(neighbors.contains(Character.toString(BURNING))){
						newRow+= BURNING;
						break;
					}
				}else if(i == thisRow.length() - 1){//last char
					neighbors+= rowAbove == null ? "" : rowAbove.substring(i - 1, i + 1);
					neighbors+= thisRow.charAt(i - 1);
					neighbors+= rowBelow == null ? "" : rowBelow.substring(i - 1, i + 1);
					if(neighbors.contains(Character.toString(BURNING))){
						newRow+= BURNING;
						break;
					}
				}else{//middle
					neighbors+= rowAbove == null ? "" : rowAbove.substring(i - 1, i + 2);
					neighbors+= thisRow.charAt(i + 1);
					neighbors+= thisRow.charAt(i - 1);
					neighbors+= rowBelow == null ? "" : rowBelow.substring(i - 1, i + 2);
					if(neighbors.contains(Character.toString(BURNING))){
						newRow+= BURNING;
						break;
					}
				}
				newRow+= Math.random() < F ? BURNING : TREE;
			}
		}
		return newRow;
	}
	
	public static List<String> populate(int width, int height){
		List<String> land = new LinkedList<String>();
		for(;height > 0; height--){//height is just a copy anyway
			StringBuilder line = new StringBuilder(width);
			for(int i = width; i > 0; i--){
				line.append((Math.random() < TREE_PROB) ? TREE : EMPTY);
			}
			land.add(line.toString());
		}
		return land;
	}
	
	public void processN(int n) {
		for(int i = 0;i < n; i++){
			land = process(land);
			try {
				Thread.sleep(750);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			repaint();
		}
	}
	
	public static void main(String[] args){
		List<String> land = Arrays.asList(".TTT.T.T.TTTT.T",
				"T.T.T.TT..T.T..",
				"TT.TTTT...T.TT.",
				"TTT..TTTTT.T..T",
				".T.TTT....TT.TT",
				"...T..TTT.TT.T.",
				".TT.TT...TT..TT",
				".TT.T.T..T.T.T.",
				"..TTT.TT.T..T..",
				".T....T.....TTT",
				"T..TTT..T..T...",
				"TTT....TTTTTT.T",
				"......TwTTT...T",
				"..T....TTTTTTTT",
				".T.T.T....TT...");
		Fire fire = new Fire(land);
		fire.processN(5);
		
		land = populate(50, 50);
		Fire fire2 = new Fire(land);
		fire2.processN(10);
	}
}

Output sample: