Simples Assim

import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.builder.xml.Namespaces;

public final class SampleRouteBuilder extends RouteBuilder {
  private static final Namespaces NS = new Namespaces("Sample", "http://fernandoribeiro.eti.br/Sample");

  @Override
  public void configure() throws Exception {
    from(...).process(new Processor() {

      public void process(final Exchange exchange) {
        final String str = (String) NS.xpath("/Sample:Element", String.class).evaluate(exchange);

        ...
      }

    });
  }

}