title: What is the difference between corePoolSize and maxPoolSize in the Spring ThreadPoolTaskExecutor
body: <p>I have to send out massEmails to all users of a website. I want to use a thread pool for each email that is sent out. Currently I have set the values to :</p>
  
  <pre><code>&lt;property name="corePoolSize" value="500" /&gt;
  &lt;property name="maxPoolSize" value="1000" /&gt;
  </code></pre>
  
  <p>What is the difference between the two and will it scale. Currently I have approx. 10000 users.</p>