Problems with charAt() in loop

[LasseA]

So I'm trying to make a program which tests if a word is a palindrome or not(like racecar is the same spelled backwards).
This is my code:

import java.util.*;
public class C4E13 {
	public static void main (String[] args) {
		Scanner console = new Scanner(System.in);
		System.out.println("Enter your word(s) and press enter to test which is palindromes");
		String word = console.next();
		printPalindrome(word);
		
	}
	
	public static void printPalindrome(String word) {
		int length = word.length();
		String reverseWord = null;
		for (int i = 0 ; i <= length ; i++) {
			char a = word.charAt(length-i);
			reverseWord = reverseWord+a;
		}
			
		if (word.equals(reverseWord)) {
			System.out.println("Yes");
		}
		
		else {
			System.out.println("No");
		}
	}
}

The error I get when I type in a word is

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 4
	at java.lang.String.charAt(String.java:658)
	at C4E13.printPalindrome(C4E13.java:15)
	at C4E13.main(C4E13.java:7)

Where the number it's out of range is equal to length of the word I type in.

What is causing the problem? I can't figure it out.

[milovan]

Look at line 14 and 15 in your code...

StringIndexOutOfBoundsException is triggered when you try to read char from position in String that don't exists.

[LasseA]

for (int i = 0 ; i <= length-1 ; i++) {
char a = word.charAt(length-i-1);
reverseWord = reverseWord+a;
}

changed it to the code above, and it seems to work now thanks :)
Well that part of the code seems to work, that's it, because if I type in "racecar" it says no, which it shouldn't

My guess is there's something that needs to change about this piece of code

reverseWord = reverseWord+a;

[milovan]

Check this
http://docs.oracle.com/javase/7/docs...ngBuilder.html
http://docs.oracle.com/javase/7/docs...ingBuffer.html

[JosAH]

Just for the fun of it: print out reverseWord just before you test it (after the loop has finished).

kind regards,

Jos

[LasseA]

Thanks for answers guys!
I figured out that I just had to write "" instead of null, I thought null would be the same as writting nothing.
So I tried printing reverseWord after loop as JosAH suggested, and I found mistake in writting null.