int数组的Java Null指针异常？

Question

目前正在为游戏拼图和龙工作，并继续遇到这个我无法创建有效个人的问题，因为我无法创建有效的孩子。问题总是回到个人试图找到2d数组位置的位置，并在Array Traverse函数中返回空指针异常。

 public class Individual {

  static int MoveLength = 5;
  int fitness = 0;
  boolean Feasibility = true;

ArrayList<Integer> Move = new ArrayList();
public int[] position = new int[2];
char[][] PuzzleMatrix;


public void GenerateIndividual(){
    PositionRandomizer();
    RandomMoves();
    MoveFollower();
   // PrintMatrix(PuzzleMatrix);
    if(this.Feasibility == false){
        GenerateIndividual();
    }
    System.out.println("sucess");
}   


public Individual(char[][] PuzzleMatrix){
    PuzzleMatrix = this.PuzzleMatrix;
}

public void MoveFollower(){
    for(int x = 0; x < Move.size(); x++){
        ArrayTraverse(Move.get(x));
    }
}

public int randomnumbergenerator(){
    int[] myArray = {0,1,2,3};
    Random generator = new Random();
    int randomIndex = generator.nextInt(myArray.length);
    return myArray[randomIndex];
}

public void PositionRandomizer(){
    /*
    http://stackoverflow.com/questions/363681/generating-random-integers-in-a-specific-range
    random position value
    */
    Random ran = new Random();
    int random = ran.nextInt(7);
    Random ran2 = new Random();
    int random2 = ran2.nextInt(7);      
    position[0] = random;
    position[1] = random2;
}

public void RandomMoves(){
    for(int x = 0; x < MoveLength; x++){
        int randomMove = randomnumbergenerator();
        Move.add(randomMove);
    }       
}

public void ArrayTraverse(int direction){
    System.out.println(direction);
    try{
        if(direction == 0){
            char original = PuzzleMatrix[position[0]][position[1]];
            char newvalue = PuzzleMatrix[position[0] - 1][position[1]];
            PuzzleMatrix[ position[0] - 1 ] [position[1]] = original;
            PuzzleMatrix[ position[0]]     [position[1]] = newvalue;
        }
        if(direction == 2){
            char original = PuzzleMatrix[position[0]][position[1]];
            char newvalue = PuzzleMatrix[position[0] + 1][position[1]];
            PuzzleMatrix[ position[0] + 1 ] [position[1]] = original;
            PuzzleMatrix[ position[0]]     [position[1]] = newvalue;
        }
        if(direction == 1){
            char original = PuzzleMatrix[position[0]][position[1]];
            char newvalue = PuzzleMatrix[position[0]][position[1] + 1];
            PuzzleMatrix[ position[0]] [position[1] + 1 ] = original;
            PuzzleMatrix[ position[0]]     [position[1]] = newvalue;
        }
        if(direction == 3){
            char original = PuzzleMatrix[position[0]][position[1]];
            char newvalue = PuzzleMatrix[position[0]][position[1] - 1];
            PuzzleMatrix[ position[0]] [position[1] - 1 ] = original;
            PuzzleMatrix[ position[0]]     [position[1]] = newvalue;
        }
    }catch(Exception e){
        System.out.println(e);
        Feasibility = false;
    }
}

public void PrintMatrix(char[][] PuzzleMatrix){

    for (int i = 0; i < PuzzleMatrix.length; i++) {
        for (int j = 0; j < PuzzleMatrix[0].length; j++) {
            System.out.print(PuzzleMatrix[i][j] + " ");
            }
        System.out.print("\n");
    }

}