title: Does Java-8 support product of elements of array
body: <p>Java-8 provides stream to sum the array as following, does the stream support <code>product</code>? If steam doesn't support, is there other way to calculate the product without manually writing my loop?</p>
  
  <pre><code>int[] a = {1, 2, 3, 4};
  int sum = IntStream.of(a).sum();
  </code></pre>