Coding Problem | Perfectly nested String

I remember this type of lexical analysis problem being in my compilers class. That said I have never used a stack in real coding but I can see various places where O(1) read/write to latest element can be useful. This problem from codility basically asks you to check if a String is properly nested.

// you can also use imports, for example:
// import java.util.*;
import java.util.Stack;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(String S) {
       Stack<Character> charStack = new Stack<Character>();
       
       for (int i=0; i < S.length(); i++)  {
           char c = S.charAt(i);
           if(c=='{')
                    charStack.push('{');
           else if(c=='[')
                    charStack.push('[');
           else if(c=='(')
                    charStack.push('(');
           else if(c=='}'){
               if(charStack.peek()=='{')
                    charStack.pop();
               else    
                    return 0;        
           }
           else if(c==']') {
               if(charStack.peek()=='[')
                    charStack.pop();
               else    
                    return 0; 
           }
           else if(c==')'){
                if(charStack.peek()=='(')
                    charStack.pop();
                else    
                    return 0; 
           }
           else {
            System.err.println("ERROR");
            return 0;
           }
       }
       
      return 1; 
    }
}