title: Soap in Groovy - keep getting NoSuchMethodError
body: <p>Newbie question: </p>
  
  <p>I'm new to groovy &amp; soap , so I might be missing out on something here: </p>
  
  <p>I'm trying to communicate with a very basic web service : </p>
  
  <pre><code>import groovy.net.soap.SoapClient
  ... 
  def proxy = new SoapClient("http://soapclient.com/xml/soapresponder.wsdl")
  res = proxy.Method1("ABC", "123");
  println (res);
  </code></pre>
  
  <p>It seems the connection works , but when I try to invoke "Method1(..)" , I keep getting </p>
  
  <pre><code>Exception in thread "main" java.lang.NoSuchMethodError: org.codehaus.groovy.runtime.InvokerHelper.getInstance()Lorg/codehaus/groovy/runtime/Invoker;
      at groovy.net.soap.SoapClient.invokeMethod(Unknown Source)
  </code></pre>
  
  <p>This is the relevant part of the WSDL:</p>
  
  <pre><code>&lt;message name="Method1"&gt;
  &lt;part name="bstrParam1" type="xsd:string"/&gt;
  &lt;part name="bstrParam2" type="xsd:string"/&gt;
  &lt;/message&gt;
  −
  &lt;message name="Method1Response"&gt;
  &lt;part name="bstrReturn" type="xsd:string"/&gt;
  &lt;/message&gt;
  −
  &lt;portType name="SoapResponderPortType"&gt;
  −
  &lt;operation name="Method1" parameterOrder="bstrparam1 bstrparam2 return"&gt;
  &lt;input message="tns:Method1"/&gt;
  &lt;output message="tns:Method1Response"/&gt;
  &lt;/operation&gt;
  &lt;/portType&gt;
  </code></pre>
  
  <p>What am I doing wrong?</p>