title: String.isBlank() replacement
body: <p>I'm trying to adapt a code which uses <code>String.isBlank(text)</code>. This method was introduced in Java 11, but my current project uses Java 8 and I don't want to upgrade. Is there anywhere the source code of the <code>isBlank</code> method or how can I replace it?</p>
  <p>I tried make a method but I'm not sure what check should I put in there:</p>
  <pre><code>/**
   * @param text - the text to check
   * @return {@code true} if {@code text} is empty or contains only white space codepoints
   */
  public static final boolean isBlank(final String text)
  {
      if (text == null || text.isEmpty())
      {
          return true;
      }
      
      for (final char c : text.toCharArray())
      {
          //Check here
      }
      
      return false;
  }
  </code></pre>