title: Replace lambda with method reference in flatMap during array mapping
body: <p>Say we have a <code>Customer</code> class:</p>
  
  <pre><code>public class Customer {
      private Car[] cars;
      // getter, setter, constructor
  }
  </code></pre>
  
  <p>and collection of customers which we need to map on cars.</p>
  
  <p>Currently I'm doing it somehow like this:</p>
  
  <pre><code>Collection&lt;Customer&gt; customers = ...
  customers.stream().flatMap(
          customer -&gt; Arrays.stream(customer.getCars())
  )...
  </code></pre>
  
  <p>It works well, but <strong>the code doesn't look elegant</strong>. I'd really like to replace it with code that uses method references which usually looks more readable and more compact. But using a field of array type makes it hard. </p>
  
  <p><strong>Question:</strong> is there any way of enhancing the <code>flatMap</code> call so it will be more readable/compact/clear?</p>