I wrote a recursive method in java to detect if a String text is a palindrome. I have implemented it using the built-in method called substring, but I cannot use that and need a work-around. Can I please get some assitance on how to implement this function without using ".substring()"? Below is my code. Thank you.

/**  * Returns a boolean value representing whether the passed in character  * sequence is a valid palindrome. A palindrome is defined as such:  * A word, phrase, or sequence that reads the same backward as forward.  *  * Palindromes are recursively defined as such:  * Case 1: An empty string or single character is considered a palindrome  * Case 2: A string is a palindrome if and only if the first and last  * characters are the same and the remaining string is also a palindrome  *  * For the purposes of this method, two characters are considered  * 'the same' if they have the same primitive value. You do not need  * to do any case conversion. Do NOT ignore spaces.  *  * This method must be computed recursively! Failure to do so will result  * in zero credit for this method.  *  * @param text The sequence that will be tested  * @return Whether the passed in word is a palindrome  * @throws IllegalArgumentException if text is null  */ public static boolean isPalindrome(String text) { if (text == null) { throw new IllegalArgumentException("text cannot be null"); } if (text.equals("") || text.length() == 1) { return true; } if (text.charAt(0) == text.charAt(text.length()-1)) { return isPalindrome(text.substring(1, text.length() - 1)); //FIX CUZ CANT USE SUBSTRING!!!!!!!! } return false; }