title: Different between changing ArrayList by setter vs. assign to itself after changed
body: <p>Can someone tell me the different below :</p>
  
  <pre><code>void change(List&lt;String&gt;strings){
     strings.add("Hello");
  }
  
  List&lt;String&gt;newString(List&lt;String&gt;strings){
     strings.add("Hello");
     return strings;
  }
  
  List&lt;String&gt;strings = new ArrayList&lt;String&gt;();
    change(strings);
  /// The different?
   List&lt;String&gt;strings = new ArrayList&lt;String&gt;();
   strings = newString(strings);
  </code></pre>