title: ORA-30625: method dispatch on NULL SELF argument is disallowed
body: <p>Oracle keeps giving me this error: </p>
  
  <blockquote>
    <p>ORA-30625: method dispatch on NULL SELF argument is disallowed</p>
  </blockquote>
  
  <p>I trying it with <code>soap_api</code> </p>
  
  <p>The code follows:</p>
  
  <pre><code>FUNCTION add_numbers (p_int_1  IN  NUMBER,
      p_int_2  IN  NUMBER)
  RETURN NUMBER
  AS  
  l_request  soap_api.t_request;
  l_response  soap_api.t_response;
  l_return    VARCHAR2(32767);
  
  l_url          VARCHAR2(32767);
  l_namespace    VARCHAR2(32767);
  l_method       VARCHAR2(32767);
  l_soap_action  VARCHAR2(32767);
  l_result_name  VARCHAR2(32767);
  BEGIN
  l_url         := 'http://192.168.1.23:8080/TestWebservice.asmx';
  l_namespace   := 'xmlns="http://192.168.1.23:8080/TestWebservice.asmx"';
  l_method      := 'add';
  l_soap_action := 'http://tempuri.org/add';
  l_result_name := 'return';
  
  l_request := soap_api.new_request(p_method       =&gt; l_method,
                              p_namespace    =&gt; l_namespace);
  
  soap_api.add_parameter(p_request =&gt; l_request,
                   p_name    =&gt; 'int1',
                   p_type    =&gt; 'xsd:integer',
                   p_value   =&gt; p_int_1);
  
  soap_api.add_parameter(p_request =&gt; l_request,
                   p_name    =&gt; 'int2',
                   p_type    =&gt; 'xsd:integer',
                   p_value   =&gt; p_int_2);
  
  l_response := soap_api.invoke(p_request =&gt; l_request,
                          p_url     =&gt; l_url,
                          p_action  =&gt; l_soap_action);
  
  l_return := soap_api.get_return_value(p_response  =&gt; l_response,
                                  p_name      =&gt; l_result_name,
                                  p_namespace =&gt; l_namespace);
  
  RETURN l_return;
  END;
  </code></pre>