Leetcode: Valid Anagram

Given two strings s and t, write a function to determine if t is an anagram of s.

For example,
s = "anagram", t = "nagaram", return true.
s = "rat", t = "car", return false.

Note:
You may assume the string contains only lowercase alphabets.

Understand the problem:
If two strings are anagram iff the sorted format is the same. 

Code (Java):

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public class Solution {     public boolean isAnagram(String s, String t) {         if (s == null || s.length() == 0) {             return t == null || t.length() == 0;         }                   if (t == null || t.length() == 0) {             return s == null || s.length() == 0;         }                   if (s.length() != t.length()) {             return false;         }                   char[] sArr = s.toCharArray();         char[] tArr = t.toCharArray();                   Arrays.sort(sArr);         Arrays.sort(tArr);                   for (int i = 0; i < sArr.length; i++) {             if (sArr[i] != tArr[i]) {                 return false;             }         }                   return true;     } }