title: Groovy maps with Integer keys - 'getAt' in DefaultGroovyMethods cannot be applied to (java.lang.Integer)
body: <p>I've just started to practice Groovy and I have a question related to maps and IDEA IDE.</p>
  
  <p>Why IDEA shows me the notification below when I try to use <code>Integer</code> as a key for a map? This simple Groovy script works fine and print correct result.</p>
  
  <p><a href="https://i.stack.imgur.com/RFfxP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/RFfxP.png" alt="screenshot"></a></p>
  
  <pre><code>list = [4, 7, 3, 7, 7, 1, 4, 2, 4, 2, 7, 5]
  
  map = [:]
  list.each {
      t = map[(it)]
      map[(it)] = t != null ? t + 1 : 1
  }
  
  map.each {key, value -&gt; if (value == 1) println key}
  </code></pre>