title: vaadin8 DateField: Cannot cast java.time.LocalDate to java.util.Date
body: <p>I have simple entity (for example)</p>
  
  <pre><code> import java.util.Date;
   class People implements Serializable{
     ...
     private Date birthdate; //(getters, setters)
     ...}
  </code></pre>
  
  <p>UI code:</p>
  
  <pre><code> final Binder&lt;People&gt; binder = new Binder&lt;People&gt;(People.class);  ...
   People bean=new  People();
   binder.setBean(bean);
   DateField birthdate = new DateField("date of birth");
   binder.bind(birthdate, "birthdate");
  </code></pre>
  
  <p>When I select date from calendar in UI I get:</p>
  
  <pre><code> Caused by: java.lang.ClassCastException: Cannot cast java.time.LocalDate to java.util.Date
  at java.lang.Class.cast(Class.java:3369)
  at com.vaadin.data.Binder$BindingBuilderImpl.lambda$createConverter$f6099586$1(Binder.java:800)
  at com.vaadin.data.Converter.lambda$null$fdd4de71$1(Converter.java:105)
  at com.vaadin.data.Result.of(Result.java:91)
  </code></pre>
  
  <p>I tried to use</p>
  
  <pre><code> DateField birthdate = new DateField("birthdate");
   binder.bind(birthdate, "birthdate");
   binder.forField(birthdate).withConverter(new LocalDateToDateConverter());
  </code></pre>
  
  <p>but have same result. 
  How to bind  Date to DateField properly?</p>