堆栈溢出错误，m-ary树大小

Question

我的递归逻辑出了什么问题？

我正试图找到m-ary树的大小。 MTree节点的子节点由我实现的ArrayList表示。我的逻辑是for循环与m一样大，所以我可以检查每个孩子。

public AnyType element;
public int m; // MTreeNode will have m children at most
public static ArrayList<MTreeNode> children;


public MTreeNode(AnyType element, int m, ArrayList<MTreeNode> children){
  this.element = element;
  this.m = m;
  this.children = children;

public static int size(MTreeNode<?> t){
  int nodes = 0;

  if(t == null)
     return 0;

  else{
     for(int i = 0; i < t.m; i++){
        size(t.children.get(i));
     }
     return 1 + nodes;
  }
}

我在

收到错误

size(t.children.get(i));