Check if 2 strings are anagrams

Method to check if two given strings are anagrams or not.
public boolean isAnagram(String first, String second) {
if (null == first || null == second) {
return false;
}
int firstLen = first.length();
int secondLen = second.length();

if (firstLen != secondLen) {
return false;
}

char [] firstArr = first.toLowerCase().toCharArray();
char [] secondArr = second.toLowerCase().toCharArray();

Arrays.sort(firstArr);
Arrays.sort(secondArr);

for (int i=0; i<firstLen; i++) {
if (firstArr[i] != secondArr[i]) {
return false;
}
}
return true;
}