title: Grails / GORM: difference between lazy: false & fetchMode eager
body: <p>In Grails / GORM, what is the difference between <code>static mapping = {xyz lazy: false}</code> &amp; <code>static fetchMode = [xyz: 'eager']</code>?</p>
  
  <p>Example:</p>
  
  <pre><code>class Book {
      static belongsTo = [author: Author]
      static mapping   = {author  lazy: false}
      static fetchMode = [author: 'eager']
  }
  </code></pre>