Thread: Palindromes?

My problem is that tthe commented out replace all methods cause errors.

/**
 * Write a description of class RecursivePalindrome here.
 * 
 * @author (Landon L) 
 * @version (12/7/13)
 */
public class RecursivePalindrome
{
    /**
     * Constructor for objects of class RecursivePalindrome
     */
    public RecursivePalindrome()
    {
    }
    public boolean isPalindrome(String word)
    {
        word = isPalindromeHelper(word);
        int a = word.length();
        if(a == 0 || a == 1)
            return true;
        if(word.charAt(0)== word.charAt(a-1))
           return isPalindrome(word.substring(1, a - 1));
        else
        return false;
    }
    public String isPalindromeHelper(String word)
    {
        word = word.toLowerCase();
        word = word.replaceAll(",","");
        word = word.replaceAll(".","");
        word = word.replaceAll("!","");
        word = word.replaceAll(" ","");
        word = word.replaceAll("\"\"","");
        word = word.replaceAll("'","");
        word = word.replaceAll(",","");
        //word = word.replaceAll("?","");
        //word.replaceAll("(","");
        //word.replaceAll(")","");
        return word;  
    }
}

import java.util.*;
public class RecursivePalindromeTester
{
    public static void main(String[] args)
    {
      RecursivePalindrome recP = new RecursivePalindrome();
      Scanner in = new Scanner(System.in);
      System.out.println("Type in word or phrase?(\"q\" to quit)");
      String word = in.next();
      if(word.charAt(0)!='q')
      {
        if(recP.isPalindrome(word))
           System.out.println("This is a palindrome.");
        else
           System.out.println("This isn't a palindrome.");
      }
      else
      {
      System.out.println("Thanks. Come again, later!");   
      System.exit(0);
      }
    }
}

so example of implementation

thankks ill test it

--- Update ---

it works with word.replace("String", "With Str") no matter how many occurrences but I dont understand how(I mean I dont think it should work

oh i see my teacehr never mentioned regex but showed us a way to remove all vowels. I didnt realize it worked for everything and could be changed.
this is what I learned string.replaceAll("[aeiou]", "");