GameOfLife.java errors

//package uk.ac.cam.jm2129.oop.tick1;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class GameOfLife
{
    private PatternStore mStore;
    private World mWorld;
    private ArrayList<World> mCachedWorlds;
    public GameOfLife(PatternStore ps)
    {
        mStore = ps;
    }
    private World copyWorld(boolean useCloning) throws PatternFormatException, CloneNotSupportedException
    {
        World worldCopy = null;
        if (useCloning == false)
        {
            if (mWorld instanceof PackedWorld)
            {
                worldCopy = new PackedWorld((PackedWorld) mWorld);
                mCachedWorlds.add(worldCopy);
            } else if (mWorld instanceof ArrayWorld)
            {
                worldCopy = new ArrayWorld((ArrayWorld) mWorld);
                mCachedWorlds.add(worldCopy);
            }
        }
        else
        {
            if (mWorld instanceof PackedWorld)
            {
                worldCopy = (PackedWorld) mWorld.clone();
                mCachedWorlds.add(worldCopy);
            } else if (mWorld instanceof ArrayWorld)
            {
                worldCopy = (ArrayWorld) mWorld.clone();
                mCachedWorlds.add(worldCopy);
            }
        }
        return worldCopy;

    }
    public void play() throws IOException, PatternNotFound, PatternFormatException, CloneNotSupportedException
    {
        String response="";
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Please select a pattern to play (l to list:");
        while (!response.equals("q"))
        {
                response = in.readLine();
                System.out.println(response);
                if (response.equals("f"))
                {
                    int k = mWorld.getGenerationCount();
                    if (mWorld==null) {System.out.println("Please select a pattern to play (l to list):");}
                    else if (k+1 < mCachedWorlds.size())
                    {
                        mWorld = mCachedWorlds.get(k+1);
                        print();
                    }
                    else
                    {
                        mWorld.nextGeneration();
                        copyWorld(true);
                        print();
                    }
                }
                else if (response.equals("l")) {
                        List<Pattern> names = mStore.getPatternsNameSorted();
                        int i=0;
                        for (Pattern p : names) {
                                System.out.println(i+" "+p.getName()+"  ("+p.getAuthor()+")");
                                i++;
                        }
                }
                else if (response.startsWith("p"))
                {
                    mCachedWorlds = new ArrayList<World>();
                    List<Pattern> names = mStore.getPatternsNameSorted();
                    String stringOfInt = response.substring(2);
                    int patternNumber = Integer.parseInt(stringOfInt);
                    // TODO: Get the associated pattern
                    if (patternNumber <= names.size())
                    {
                       int i = 0;
                       for (Pattern p : names)
                       {
                           if (i == patternNumber)
                           {
                               Pattern myPattern = p;
                               int width = myPattern.getWidth();
                               int height = myPattern.getHeight();
                               int worldSize = width*height;
                               if (worldSize > 64)
                               {
                                   mWorld = new ArrayWorld(myPattern);
                                   copyWorld(true);
                                   print();
                               }
                               else if ((worldSize > 0) && (worldSize < 65))
                               {
                                   mWorld = new PackedWorld(myPattern);
                                   copyWorld(true);
                                   print();
                               }

                           } else {i++;}
                       }
                   } else {throw new PatternNotFound("Sorry, there is no Pattern associated with this number");}
                }
                else if (response.equals("b"))
                {
                    int k = mWorld.getGenerationCount();
                    if (k == 0) {print();}
                    else
                    {
                        k-=1;
                        World worldCopy = mCachedWorlds.get(k);
                        mWorld = worldCopy;
                        print();
                    }
                }
        }
    }
    public void print() throws IOException, PatternNotFound, PatternFormatException, CloneNotSupportedException
    {
        System.out.println("- "+mWorld.getGenerationCount());
        for (int row = 0; row < mWorld.getHeight(); row++)
        {
            for (int col = 0; col < mWorld.getWidth(); col++)
            {
                System.out.print(mWorld.getCell(col, row) ? "#" : "_");
            }
            System.out.println();
        }
        play();
    }
    public static void main(String args[]) throws IOException, PatternNotFound, PatternFormatException, CloneNotSupportedException
    {
        if (args.length!=1)
        {
            System.out.println("Usage: java GameOfLife <path/url to store>");
            return;
        }

        try
        {
            PatternStore ps = new PatternStore(args[0]);
            GameOfLife gol = new GameOfLife(ps);
            gol.play();
        }
        catch (IOException ioe)
        {
            System.out.println("Failed to load pattern store");
        }
    }
}