Find the minimum path sum for Binary Search Tree (From root to leaf)

SumOfMinimumPathBST.java

public static int minPathSum(TreeNode root) {
        if(root == null) return 0;
        int sum = root.val;
        int leftSum = Integer.MAX_VALUE;
        int rightSum = Integer.MAX_VALUE;
        if(root.right==null && root.left==null) {
            return sum;
        }else{

            if(root.left!=null){
                leftSum = minPathSum(root.left);
            }
            if (root.right!=null){
                rightSum = minPathSum(root.right);
            }
            if(leftSum < rightSum){
                sum += leftSum;
            }else{
                sum += rightSum;
            }
        }

        return sum;
    }