Java Data Type - 如何检查2个字符串是否包含相同的字符

import java.util.Arrays;

public class Main {
  public static void main(String[] args) {
    String str = "Result";
    String str1 = "rEsLtu";

    char[] firstString = str.toLowerCase().toCharArray();
    char[] secondString = str1.toLowerCase().toCharArray();

    Arrays.sort(firstString);
    Arrays.sort(secondString);

    if (Arrays.equals(firstString, secondString) == true) {
      System.out.println("same");
    } else {
      System.out.println("different");
    }
  }
}