Bracket validator java. Check if code brackets match java

BracketValidator.java

package com.company;

import java.io.*;
import java.util.*;
import java.util.stream.*;


class Result {

    /*
     * Complete the 'isBalanced' function below.
     *
     * The function is expected to return a STRING.
     * The function accepts STRING s as parameter.
     */

    public static String isBalanced(String s) {
        // Write your code here
        Stack<String> h = new Stack();
        for (String f : s.split("")) {
            switch (f) {
                case ")":
                    if(!h.empty()&&h.peek().contentEquals("(")){
                        h.pop();
                    }else{
                        return "NO";
                    }
                    break;
                case "}":
                    if(!h.empty()&&h.peek().contentEquals("{")){
                        h.pop();
                    }else{
                        return "NO";
                    }
                    break;
                case "]":
                    if(!h.empty()&&h.peek().contentEquals("[")){
                        h.pop();
                    }else{
                        return "NO";
                    }
                    break;
                default:
                    h.push(f);
            }


        }
        return h.empty()?"YES":"NO";
    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = null;
        try {
            File f = new File("s.txt");
            if (!f.exists()) {
                System.out.println(f.createNewFile());

            }
            bufferedWriter = new BufferedWriter(new FileWriter(f.getName()));
        } catch (IOException e) {
            e.printStackTrace();
        }
        int t = Integer.parseInt(bufferedReader.readLine().trim());

        BufferedWriter finalBufferedWriter = bufferedWriter;
        IntStream.range(0, t).forEach(tItr -> {
            try {
                String s = bufferedReader.readLine();

                String result = Result.isBalanced(s);

                finalBufferedWriter.write(result);
                finalBufferedWriter.newLine();
            } catch (IOException ex) {
                System.out.println(ex.getMessage());
                throw new RuntimeException(ex);
            }
        });

        bufferedReader.close();
        bufferedWriter.close();
    }
}