Java Algorithms Bracket Checker

import java.util.Stack;

class BracketChecker {
   private String input; // input string

   public BracketChecker(String in) // constructor
   {/*  ww w  .  jav  a2s .co m*/
      input = in;
   }

   public void check() {
      Stack<Character> theStack = new Stack<>(); // make stack

      for (int j = 0; j < input.length(); j++) // get chars in turn
      {
         char ch = input.charAt(j); // get char
         switch (ch) {
         case '{': // opening symbols
         case '[':
         case '(':
            theStack.push(ch); // push them
            break;

         case '}': // closing symbols
         case ']':
         case ')':
            if (!theStack.isEmpty()) {
               char chx = theStack.pop(); // pop and check
               if ((ch == '}' && chx != '{') || (ch == ']' && chx != '[') || (ch == ')' && chx != '('))
                  System.out.println("Error: " + ch + " at " + j);
            } else // prematurely empty
               System.out.println("Error: " + ch + " at " + j);
            break;
         default: // no action on other characters
            break;
         } 
      } 
      if (!theStack.isEmpty())
         System.out.println("Error: missing right delimiter");
      else {
         System.out.println("no error");
      }
   }
}

public class Main {
   public static void main(String[] args) {
      BracketChecker theChecker = new BracketChecker("(a+b)+{(4+5)+r[1]+a()}")  ;
      theChecker.check(); // check brackets
   }
}