title: How to sum a list of integers with java streams?
body: <p>I want to sum a list of Integers. It works as follows, but the syntax does not feel right. Could the code be optimized?</p>
  <pre><code>Map&lt;String, Integer&gt; integers;
  integers.values().stream().mapToInt(i -&gt; i).sum();
  </code></pre>