title: What's the meaning of 'Chunk * _chunk = new (size) Chunk(size)'?
body: <p>There is a c++ code shown below:</p>
  
  <pre><code>Chunk * _chunk = new (size) Chunk(size);
  </code></pre>
  
  <p>I don't understand the first '(size)' following the 'new',What's the meaning of it?
  The code above is from JDK8.</p>