title: Concurrent updates on Collection
body: <p>I am developing a System and it has <code>ArrayList</code> that access in several places(inserting, removing and updates the values). Due to access of <code>ArrayList</code> in several places when i run the program it gives Concurrent update error. </p>
  
  <p>Instead of <code>ArrayList</code> I can use <code>Vector</code> because <code>Vector</code> is synchronized. But if i use <code>Vector</code> will It be cause to decrease the performance of the system? Give me Ideas. How I can solve this issue? </p>
  
  <p>This is part of the exception I get:</p>
  
  <pre class="lang-none prettyprint-override"><code>].[localhost].[/uckt].[Faces Servlet]] (http-127.0.0.1-8080-144) 
  Servlet.service() for servlet Faces Servlet threw exception: java.util.ConcurrentModificationException
  at java.util.ArrayList$Itr.checkForComodification(Unknown Source) [:1.7.0_02]
  at java.util.ArrayList$Itr.next(Unknown Source) [:1.7.0_02] 
  </code></pre>