title: Java 8, Streams to find the duplicate elements
body: <p>I am trying to list out duplicate elements in the integer list say for eg,</p>
  
  <pre><code>List&lt;Integer&gt; numbers = Arrays.asList(new Integer[]{1,2,1,3,4,4});    
  </code></pre>
  
  <p>using Streams of jdk 8. Has anybody tried out. To remove the duplicates we can use the distinct() api. But what about finding the duplicated elements ? Anybody can help me out ?</p>