title: What is the difference between ImportSelector and ImportBeanDefinitionRegistar in Spring?
body: <ol>
  <li><p>What is the difference between <code>ImportSelector</code> and <code>ImportBeanDefinitionRegistar</code>?</p></li>
  <li><p>Which scenario should be use <code>ImportSelector</code> or <code>ImportBeanDefinitionRegistar</code> and why?</p></li>
  </ol>