string array to string java

public class ArrayOfStrings {
   public static void main(String args[]) {
      String stringArray[] = {"Hello ", " how", " are", " you", " welcome", " to", " Tutorialspoint"};
      StringBuffer sb = new StringBuffer();
      for(int i = 0; i < stringArray.length; i++) {
         sb.append(stringArray[i]);
      }
      String str = sb.toString();
      System.out.println(str);
   }
}

String str = String.join(",", arr);