StackerDacker

/**
 * Dacks the stack in order to wack the crack.
 *
 * @author Ulizio
 * @version 1.0
 */
//Imports
import java.io.*;
import java.util.Scanner;
import java.util.*;
public class StackerDacker
{
    public static void main (String [] args) {

        /*
         * Entire program works very well, except, when the stack tries to pop and there is nothing there
         * rather than return null it throws a null pointer exception.
         *
         * When run with too many opening parentheses: Success
         * When run with correct number of parentheses: Null Pointer Exception
         * When run with too many closing parentheses: Null Pointer Exception
         *
         * Conclusion: Stack may be null
         */

        try {
            Scanner scan = new Scanner(new BufferedReader(new FileReader("file.txt")));
            String input = scan.nextLine();
            int length = input.length();

            Stack<Integer> x = new Stack<Integer>();

            int i;

            for(i = 0; i<length; i++) {
                String temp = input.substring(i,i+1);
                if(temp.equals("(")) {
                    x.push(1);
                }
                if(temp.equals(")")) {
                    if (x.pop().equals(null)) {
                        System.out.println("There appear to be too many closing parentheses.");
                    }
                    else {
                        x.pop();
                    }
                }
                else{

                }
            }

            if (x.peek() != (null)) {
                System.out.println("There appear to be too many opening parentheses.");
            }
            else {
                System.out.println("This code appears to check out.");
            }

        }
        catch(Exception e) {
            System.out.println("Critical: " + e);
        }
    }
}