title: Ids must exist in the Container or as a generated column
body: <p>I'm developing an vaadin application, and now I'm not able to resolve the following problem.</p>
  
  <p>I have my object model:</p>
  
  <pre><code>public class MyModel {
  
      private long id;
      private Date dValidoAl;
  
      public long getId() {
          return id;
      }
  
      public void setId(long id) {
          this.id = id;
      }
  
      public Date getDValidoAl() {
          return dValidoAl;
      }
  
      public void setDValidoAl(Date dValidoAl) {
          this.dValidoAl = dValidoAl;
      }
  
  }
  </code></pre>
  
  <p>Now I'm trying to bind this object to a <code>BeanItemContainer</code> in this way:</p>
  
  <pre><code>Table table = new Table();
  BeanItemContainer&lt;MyModel&gt; container = new BeanItemContainer&lt;MyModel&gt;(MyModel.class);
  table.setContainerDataSource(container);
  
  Object[] visibleProperties = new Object[] { "id", "dValidoAl" };
  String[] columnsHeader = new String[] { "Id", "Inizio Validità" };
  table.setVisibleColumns(visibleProperties);
  table.setColumnHeaders(columnsHeader);
  </code></pre>
  
  <p>but I get this error:</p>
  
  <blockquote>
    <p>Ids must exist in the Container or as a generated column, missing id: dValidoAl</p>
  </blockquote>
  
  <p>Where am I doing wrong?</p>