title: Failed to create route route1
body: <p>i have a trouble solving this exception and i don't know where i'm doing wrong. 
  here's the Exception.</p>
  
  <pre><code>org.apache.camel.spring.boot.CamelSpringBootInitializationException: java.lang.RuntimeException: org.apache.camel.FailedToCreateRouteException: Failed to create route route1 at: &gt;&gt;&gt; Filter[bean[ref:filter method:accept] -&gt; []] &lt;&lt;&lt; in route: Route(route1)[[From[file:D:/copyy/?noop=true]] -&gt; [Filter[be... because of Definition has no children on Filter[bean[ref:filter method:accept] -&gt; []]
  
  Caused by: org.apache.camel.FailedToCreateRouteException: Failed to create route route1 at: &gt;&gt;&gt; Aggregate[true -&gt; []] &lt;&lt;&lt; in route: Route(route1)[[From[file:D:/xml/?noop=true]] -&gt; [Aggregate[t... because of Definition has no children on Aggregate[true -&gt; []]
  Caused by: java.lang.IllegalArgumentException: Definition has no children on Aggregate[true -&gt; []]
  </code></pre>
  
  <p>and here's my router :</p>
  
  <pre><code>&lt;bean id="AggregatorDemo" class="com.javainuse.AggregatorDemo"/&gt; 
  &lt;route&gt;
      &lt;from uri="file:D:/xml/?noop=true" /&gt;
          &lt;aggregate strategyRef="AggregatorDemo"&gt;
          &lt;correlationExpression&gt;
          &lt;constant&gt;true&lt;/constant&gt;
          &lt;/correlationExpression&gt;
          &lt;/aggregate&gt;
          &lt;log message=".....${body}...."&gt;&lt;/log&gt;
          &lt;to uri="file:D:/Xmlcopy" /&gt;
  &lt;/route&gt;
  </code></pre>
  
  <p>and here's the aggregator class i'm using.</p>
  
  <pre><code>public class AggregatorDemo implements AggregationStrategy{
  
   public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
  
          if (oldExchange == null) {
  
              return newExchange;
          }
  
          String orders = oldExchange.getIn().getBody(String.class);
          String newLine = newExchange.getIn().getBody(String.class);
  
  
          orders = orders+ newLine;
  
          oldExchange.getIn().setBody(orders);
  
  
          return oldExchange;
   }
  </code></pre>
  
  <p>}</p>