title: sum of BigDecimal List using streams and sum method
body: <p>If we have all int or long or other primitive datatype value in list then we obtain sun of all values using</p>
  
  <pre><code>return items.stream().mapToInt(i -&gt; i).sum();
  </code></pre>
  
  <p>I have list of BigDecimal values,how to find the sum of all values using <code>Java8</code> </p>
  
  <p>As there is no default method like mapToBigDecimal I tried to create plain map but then I cannot use <code>sum()</code> </p>