title: Exception java.lang.NoSuchMethodError: org.apache.wicket.AttributeModifier.append(Ljava/lang/String;Ljava/io/Serializable;)
body: <p>I tried to use an ObjectAutoCompleteBuilder to build ObjectAutoCompleteField as below:</p>
  
  <pre><code>ObjectAutoCompleteBuilder builder = new ObjectAutoCompleteBuilder(provider);
      builder.autoCompleteRenderer(renderer);
  
      final ObjectAutoCompleteField autocompleteField = builder.build("searchResource" , new Model());
      final TextField searchResource = autocompleteField.getSearchTextField();
      searchResource.setRequired(true);
  </code></pre>
  
  <p>but it has thrown this exception :</p>
  
  <pre><code>java.lang.NoSuchMethodError: org.apache.wicket.AttributeModifier.append(Ljava/lang/String;Ljava/io/Serializable;)Lorg/apache/wicket/behavior/AttributeAppender;
  </code></pre>
  
  <p>Does anyone have any idea why?</p>