import java.lang.*; import java.util.*; class Palindrome { public static boolean isPalindrome(String s) { s = s.toLowerCase(); char[] nonAlpha = s.toCharArray(); ArrayList alpha = new ArrayList(); for (char c : nonAlpha) { if (Character.isLetter(c)) alpha.add(c); } int i = 0; int j = alpha.size() - 1; while (i < j) { if (alpha.get(i) != alpha.get(j)) return false; i++; j--; } return true; } public static void main(String[] args) { String s = "A man, a plan, a canal: Panama"; System.out.println(isPalindrome(s)); } }