Check string for palindrome

Question

A palindrome is a word, phrase, number or other sequence of units that can be read the same way in either direction.

To check whether a word is a palindrome I get th

Answer 1

You can check if a string is a palindrome by comparing it to the reverse of itself:

public static boolean isPalindrome(String str) {
    return str.equals(new StringBuilder(str).reverse().toString());
}

or for versions of Java earlier than 1.5,

public static boolean isPalindrome(String str) {
    return str.equals(new StringBuffer().append(str).reverse().toString());
}

EDIT: @FernandoPelliccioni provided a very thorough analysis of the efficiency (or lack thereof) of this solution, both in terms of time and space. If you're interested in the computational complexity of this and other possible solutions to this question, please read it!