Java balanced expressions check {[()]}

Question

I am trying to create a program that takes a string as an argument into its constructor. I need a method that checks whether the string is a balanced parenthesized expressio

Answer 1

public void validateExpression(){

    if(!str.isEmpty() && str != null){
        if( !str.trim().equals("(") && !str.trim().equals(")")){

            char[] chars = str.toCharArray();

            for(char c: chars){
                if(!Character.isLetterOrDigit(c) && c == '('  || c == ')') {
                    charList.add(c);
                }
            }

            for(Character ele: charList){                   
                if(operatorMap.get(ele) != null && operatorMap.get(ele) != 0){                      
                    operatorMap.put(ele,operatorMap.get(ele)+1);
                }else{
                    operatorMap.put(ele,1);
                }
            }

            for(Map.Entry ele: operatorMap.entrySet()){
                System.out.println(String.format("Brace Type \"%s\" and count is \"%d\" ", ele.getKey(),ele.getValue()));                   
            }

            if(operatorMap.get('(') == operatorMap.get(')')){
                System.out.println("**** Valid Expression ****");
            }else{
                System.out.println("**** Invalid Expression ****");
            }

        }else{
            System.out.println("**** Incomplete expression to validate ****");
        }

    }else{
        System.out.println("**** Expression is  empty or null ****");
    }       
}