title: Important topics/APIs list for Java interview
body: <p>This is little different from what already been asked for <a href="https://stackoverflow.com/questions/706190/java-books-for-preparing-for-interviews">here</a>  </p>
  
  <p>I would like to know what topics/APIs are most important for Java interviews. for example - </p>
  
  <ul>
  <li><strong>Concurrency</strong>,   </li>
  <li><strong>Collections</strong><br>
  .....and like that.  </li>
  </ul>
  
  <p>The reason is because implementations like <code>ConcurrentHashMap</code> (read <a href="http://www.ibm.com/developerworks/java/library/j-jtp08223/" rel="nofollow noreferrer">here</a>) have so much details in them, that one would like to discuss about them as it covers many important aspects</p>