title: Groovy - Add Map Entry with Iterator
body: <p>Please explain, why this isn't working (Groovy 2.0.5 on JDK7). I just want to add some map entries from a list. </p>
  
  <pre><code>def map = new HashMap&lt;String,String&gt;()
  map &lt;&lt; ["key":"value"]
  
  def list = ["a","b","c"]
  list.each {
      map &lt;&lt; [it:"value"]
  }
  println map
  println map.a
  println map.containsKey("a")
  
  /*
  [key:value, a:value, b:value, c:value]
  null        &lt;- ?
  false       &lt;- ?
  */
  </code></pre>
  
  <p>It is also not working with:</p>
  
  <pre><code>map &lt;&lt; ["$it":"value"]
  </code></pre>
  
  <p>But it is working with:</p>
  
  <pre><code>map &lt;&lt; [(""+it):"value"]
  </code></pre>
  
  <p>???</p>