Stack Practice in java

Today practiced the Stack in java and try the problem to check the balanced brackets
here's is an code :

import java.util.Scanner;
import java.util.Stack;
import java.util.StringTokenizer;

public class brackets {
static boolean isvalid(String s){

    Stack<Character> stack=new Stack<>();
    for (char i:s.toCharArray()){
        if(i =='{' || i=='['){
            stack.push(i);
        }
        else {
            if (stack.isEmpty()) {
                return false;
            }
            char top = stack.pop();
            if (i == '}' && top != '{' || i == ']' && top != '[') {
                return false;
            }
        }
    }
    return stack.isEmpty();
}
public static void main(String[] args) {
    Scanner in=new Scanner(System.in);
    System.out.println("Enter the string :");
    String s= in.nextLine();
    System.out.println(isvalid(s));

}

}

java

stack

javastack

balancedstack

leetcode