how do you check whether two strings are anagram to each other?

Problem statement:
Given two Strings S1 and S2. You have to check whether these two strings are anagram to each other?

1. import java.util.ArrayList;
2. import java.util.Arrays;
3. public class Anagram {
4.     public static void main(String[] args) {
5.         String S1 = "LISTEN";
6.         String S2 = "SILENT";
7.         if (areAnagram(S1, S2)) {
8.             System.out.println("Anagram");
9.         } else {
10.             System.out.println("Not an Anagram");
11.         }
12.     }
13.     static boolean areAnagram(String s1, String s2) {
14.         char c1[] = s1.toCharArray();
15.         char c2[] = s2.toCharArray();
16.         int n1 = c1.length;
17.         int n2 = c2.length;
18.         if (n1 != n2)
19.             return false;        
20.         Arrays.sort(c1);
21.         Arrays.sort(c2);        
22.         for (int i = 0; i < n1; i++)
23.             if (c1[i] != c2[i])
24.                 return false;
25.         return true;
26.     }
27. }

Output: 

Anagram