title: No instance(s) of type variable(s) T exist so that List<T> conforms to Integer
body: <p>In the following code:</p>
  
  <pre><code>return new HashSet&lt;&gt;(namedParameterJdbcTemplate.query(
      SOME_SQL_QUERY_STRING,
      parametersMap,
      (resultSet, rowNum) -&gt; resultSet.getBigDecimal("GETID")
  ));
  </code></pre>
  
  <p>I'm getting a red line under <code>(resultSet, rowNum) -&gt; resultSet.getBigDecimal("GETID"))</code> and the following error : <code>No instance(s) of type variable(s) T exist so that List&lt;T&gt; conforms to Integer</code>. Can someone please help me and tell why this is happening?</p>