title: RemoveIf generate an exception, why?
body: <p>I try to remove an item from a list using lambda expression but removeIf generate an exception, why?</p>
  
  <p>In this Orlacle video jdk8 8 MOOC  introduce removeif with list and not arraylist.  Is it right ? <a href="https://youtu.be/olKF7VpJMfg?list=PLMod1hYiIvSZL1xclvHcsV2dMiminf19x&amp;t=137" rel="nofollow noreferrer">https://youtu.be/olKF7VpJMfg?list=PLMod1hYiIvSZL1xclvHcsV2dMiminf19x&amp;t=137</a>   </p>
  
  <pre><code>public static void main(String[] args){
          List&lt;String&gt; parole = Arrays.asList("Lambda ", "expressions ", "are ", "cool ");
  Predicate &lt;String&gt; findAre= s-&gt;"are ".equals(s);         
          parole.removeIf(findAre);
          parole.forEach( System.out::println);
              }
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/FbBZ5.png" rel="nofollow noreferrer">Here pict with code and Exception in thread "main" </a></p>