Game 3x3

Hallo, I am doing GamingTable size 3x3(look at the picture)http://img704.imageshack.us/img704/5...mingtabled.jpg. And i need generate some solution but i don´t know how can i do this. Target is find the best algorithm for solution.
My code:
Main class

Code :

public class Main {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        try {
            GamingTable g1 = new GamingTable(3);
            System.out.println(g1);
            g1.move(GamingTable.Direction.UP);
            System.out.println("Done");
            System.out.println(g1);
        } catch (NotPossibleMoveException ex) {
            System.out.println("Not done");
        }
 
 
    }
 
}

Class GamingTable

Code :

public class GamingTable {
    private short data [][];
    private int positionX;
    private int positionY;
    private final int EMPTY = -1;
    public enum Direction {UP, DOWN, LEFT, RIGHT}
 
    public GamingTable(int size)
    {
        data = new short[size][size];
        short counter = 1;
        for (int y = 0; y < size; y++)
        {
            for (int x = 0; x < size; x++)
            {
                data[x][y]=counter++;
            }
 
        }
        positionX = size - 1;
        positionY = size - 1;
        data[positionX][positionY] = EMPTY;
    }
 
    public GamingTable()
    {
        this(4);
    }
 
    public GamingTable(GamingTable g)
    {
        this.positionX = g.positionX;
        this.positionY = g.positionY;
        this.data= new short[g.data.length][g.data.length];
        for (int i = 0; i < data.length; i++)
        {
            System.arraycopy(g.data[i],0,this.data[i],0,data[i].length);
        }
    }
 
    public GamingTable(short[][] data, int startX, int startY) throws InvalidTableConfigurationException
    {
        if(data.length < 1 || data.length != data[0].length || data[startX][startY] != EMPTY)
            throw new InvalidTableConfigurationException();
        this.positionX = startX;
        this.positionY = startY;
        this.data = new short[data.length][data.length];
        for (int y = 0; y < data.length; y++)
        {
            for (int x = 0; x < data.length; x++)
            {
                this.data[x][y] = data[y][x];
            }
 
        }
    }
 
    @Override
    public String toString()
    {
        String s = "";
        for (int y = 0; y < data.length; y++)
        {
            for (int x = 0; x < data.length; x++)
            {
                s += data[x][y];
            }
            s +="\n";
 
        }
        return s;
    }
 
    public int fitness()
    {
        int fitness = 0;
        short counter = 1;
        for (int y = 0; y < data.length; y++)
        {
            for (int x = 0; x < data.length; x++)
            {
                if(data[x][y] == counter)
                {
                    fitness ++;
                }
                counter ++;
            }
 
        }
        return fitness;
    }
 
    public boolean isSolution()
    {
        return fitness() == data.length * data.length -1;
    }
 
    public void move(Direction dir) throws NotPossibleMoveException
    {
        switch(dir)
        {
            case UP:
                if(positionY <= 0) throw new NotPossibleMoveException();
                swap(positionX, positionY, positionX, positionY-1);
                positionY -= 1;
                break;
            case DOWN:
                if(positionY >= data.length-1) throw new NotPossibleMoveException();
                swap(positionX, positionY, positionX, positionY+1);
                positionY += 1;
                break;
            case LEFT:
                if(positionX <= 0) throw new NotPossibleMoveException();
                swap(positionX, positionY, positionX-1, positionY);
                positionX -= 1;
                break;
            case RIGHT:
                if(positionX >= data.length-1) throw new NotPossibleMoveException();
                swap(positionX, positionY, positionX+1, positionY);
                positionX += 1;
                break;
        }
    }
 
    private void swap(int x1, int y1, int x2, int y2)
    {
        short tmp = data[x1][y1];
        data[x1][y1] = data [x2][y2];
        data[x2][y2] = tmp;
    }
 
 
}

Class Solver

Code :

public class Solver implements ISolver {
 
}

Interface ISolver

Code :

interface ISolver {
 
}