A path in a binary tree that sums to a value

Input a binary tree and an integer, print out all paths in the binary tree whose sum of node values ​​is the input integer. A path is defined as a path from the root node of the tree down to the nodes passed by the leaf nodes.
Parse:

import java.util.ArrayList;
import java.util.Stack;

class TreeNode{
    int val =0;
    TreeNode left = null;
    TreeNode right = null;
    public TreeNode(int val) {
        this.val = val;
    }
}
//递归实现路径的遍历，用栈记录访问过的节点。


public class findBinaryTreePath {
    public ArrayList<ArrayList<Integer>> FindPath(TreeNode root,int target){
        ArrayList<ArrayList<Integer>> pathList = new ArrayList<ArrayList<Integer>>();
        if(root == null)
            return pathList;
        Stack<Integer> stack = new Stack<Integer>();
        FindPath(root,target,stack,pathList);
        return pathList;
    }

    private void FindPath(TreeNode root, int target, Stack<Integer> stack, ArrayList<ArrayList<Integer>> pathList) {
        // TODO Auto-generated method stub
        if(root == null)
            return;
        if(root.left==null && root.right==null) {//基准条件 递归结束
            if(root.val==target) {
                ArrayList<Integer> list=new ArrayList<Integer>();
                for(Integer i:stack) {
                    list.add(i);
                }
                list.add(root.val);
                pathList.add(list);

            }

        }else {                //递归演进，何时进行递归演进
            stack.push(root.val);
            FindPath(root.left,target-root.val,stack,pathList);
            FindPath(root.right,target-root.val,stack,pathList);
            stack.pop();
        }                   //无需返回值
    }


}