JAVA : Check UTF8 enconded characters in a string

UTF8Check.java

import java.util.*;
import java.util.stream.*;
import java.nio.charset.StandardCharsets;

public class UTF8Check {
  public static final String[] utf8Strings = new String[]{
    "UTF8 check",
      "@!#$%^&*()_+}{[]';:/.,?><`~1234567890-=\\|"
  };

  public static final String[] nonUtf8Strings =  new String[]{
    "Héllo",             // contains the character 'é' (U+00E9)
      "नमस्ते",          // contains the Devanagari character 'न' (U+0928)
      "Привет",           // contains the Cyrillic character 'р' (U+0440)
      "مرحبا",           // contains the Arabic character 'ح' (U+062D)
      "こんにちは",        // contains the Hiragana character 'に' (U+306B)
      "안녕하세요",         // contains the Hangul character '하' (U+D558)
      "שלום",            // contains the Hebrew character 'ל' (U+05DC)
      "سلام",            // contains the Arabic character 'م' (U+0645)
      "你好",             // contains the Chinese character '好' (U+597D)
      "สวัสดี",          // contains the Thai character 'ด' (U+0E14)
      "\uD83D\uDE00"      // contains a non-UTF-8 emoji (U+1F600)
  };

  public static boolean hasOnlyUtf8Characters(String str) {
    byte[] bytes = str.getBytes(StandardCharsets.UTF_8);

    for (byte b : bytes) {
      if ((b & 0xC0) == 0x80) {
        return false; // Non-UTF-8 character detected
      }
    }

    return true;
  }

  public static void main(String... args){
    Stream.concat(
        Arrays.stream(utf8Strings), 
        Arrays.stream(nonUtf8Strings))
      .forEach((s) -> System.out.println(String.format("%-50s : has non-utf8 characters - %s", s, !hasOnlyUtf8Characters(s))));
  }
}