title: When is `StringBuilder` is preferred instead appending `String` to `String`?
body: <p>Below are two ways how to append <code>String</code>:</p>
  
  <pre><code>String firstString = "text_0";
  String secondString = "text_1";
  String resultString = firstString + secondString;
  
  StringBuilder sb = new StringBuilder();
  sb.append(firstString).append(secondString);
  String resultString = sb.toString();
  </code></pre>
  
  <p>My question is - when is more effective to use <code>StringBuilder</code>? Let's say there are 10 strings, and I need to create one of them.</p>