2D ArrayList添加问题

Question

所以我试图为一个类编写一个俄罗斯方块克隆，我试图创建一个不同部分的arraylist，以便我可以在游戏中随机生成新的部分。出于某种原因，我无法添加我声明的＆＃34;件＆＃34; （2D int数组）到我的数组列表。这是我的代码：

    ArrayList<int[][]> pieces = new ArrayList<int[][]>(7);

    int[][] piece1 = {{0,1,0,0},
                     {0,1,0,0},
                     {0,1,0,0},
                     {0,1,0,0}};
    int[][] piece2 = {{0,1,0,0},
                     {0,1,0,0},
                     {1,1,0,0},
                     {0,0,0,0}};
    int[][] piece3 = {{0,1,0,0},
                     {0,1,0,0},
                     {0,1,1,0},
                     {0,0,0,0}};
    int[][] piece4 = {{0,1,0,0},
                     {1,1,0,0},
                     {0,1,0,0},
                     {0,0,0,0}};
    int[][] piece5 = {{0,0,0,0},
                     {1,1,0,0},
                     {0,1,0,0},
                     {0,0,0,0}};
    int[][] piece6 = {{0,0,0,0},
                     {0,1,1,0},
                     {1,1,0,0},
                     {0,0,0,0}};
    int[][] piece7 = {{0,0,0,0},
                     {0,1,1,0},
                     {0,1,1,0},
                     {0,0,0,0}};  
  void setup{ 
  pieces.add(piece1);
  pieces.add(piece2);
  pieces.add(piece3);
  pieces.add(piece4);
  pieces.add(piece5);
  pieces.add(piece6);
  pieces.add(piece7);
  }

当我运行

时

currPiece = pieces.get(int(random(pieces.size())));

如果给我一个越界错误，说我的ArrayList中没有元素。

非常感谢你！ P.S我在Processing 3中编码，它与Java只有轻微的语法差异。