Great answer, but how 'bout checking input params for runtime exceptions? With 9 test cases, you never know...

static boolean isAnagram(String A, String B) {
   //Complete the function
   Boolean retValue = false;
   if(A != null && B != null) {
       char [] arrayA = A.toLowerCase().toCharArray();
       char [] arrayB = B.toLowerCase().toCharArray();
       Arrays.sort(arrayA);
       Arrays.sort(arrayB);
       retValue = Arrays.equals(arrayA, arrayB);
   }
   return retValue;
}