Java: Solving Anagrams with streams

I have been playing with code problems. Since I'm studying for Java 11 certification, I decided to resolve the Anagrams problem using streams. Here what I do is sort the two strings characters and then making a comparison.

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public class Anagrams {     static boolean isAnagram(String a, String b) {         return sortStringChars(a).equals(sortStringChars(b));     }       static String sortStringChars(String str) {         return str.toLowerCase().chars()             .mapToObj(c -> (char) c)             .sorted()             .reduce("", (s,c) -> s.concat(String.valueOf(c)), String::concat);     }       public static void main(String[] args) {         String a = "anagram";         String b = "margana";           boolean ret = isAnagram(a, b);         System.out.println( (ret) ? "Yes, Anagrams!" : "Not Anagrams" );     } }