Finding Palindromes in an Array

Question

For this assignemnt, I think that I got it right, but when I submit it online, it doesn't list it as correct even though I checked with Eclipse.

The prompt:

Write a method isPalindrome that accepts an array of Strings as its argument and returns true if that array is a palindrome (if it reads the same forwards as backwards) and /false if not. For example, the array {"alpha", "beta", "gamma", "delta", "gamma", "beta", "alpha"} is a palindrome, so passing that array to your method would return true. Arrays with zero or one element are considered to be palindromes.

My code:

public static void main(String[] args) {
    String[] input = new String[6]; //{"aay", "bee", "cee", "cee", "bee", "aay"} Should return true
    input[0] = "aay";
    input[1] = "bee";
    input[2] = "cee";
    input[3] = "cee";
    input[4] = "bee";
    input[5] = "aay";

    System.out.println(isPalindrome(input));
}

public static boolean isPalindrome(String[] input) {
    for (int i=0; i<input.length; i++) { // Checks each element
        if (input[i] != input[input.length-1-i]){
            return false; // If a single instance of non-symmetry
        }
    }
    return true; // If symmetrical, only one element, or zero elements
}

As an example, {"aay", "bee", "cee", "cee", "bee", "aay"} returns true in Eclipse, but Practice-It! says it returns false. What is going on?

Answer 1

You cant use operator == or != to compare string object. The operators will work on the object references and not values.

public static boolean isPalindrome(String[] input) {
        for (int i=0; i<input.length; i++) { // Checks each element
            if (!input[i].equals( input[input.length-1-i])){
                return false; // If a single instance of non-symmetry
            }
        }
        return true; // If symmetrical, only one element, or zero elements
}