Calling Web Service From Oracle PL/SQL do not invoke the webservice in SOA Server

Question

Hi ,
Trying to call the webservice from oralce pl/sql Function
created a Function
Not able to invoke the web service of SOA Server .
CREATE OR REPLACE FUNCTION HelloWorld_WebServices(S_STRING Varchar2) RETURN VARCHAR2 AS 
    service_ sys.utl_dbws.SERVICE; 
    call_ sys.utl_dbws.CALL; 
    service_qname sys.utl_dbws.QNAME; 
    port_qname sys.utl_dbws.QNAME; 
    response sys.XMLTYPE; 
    request sys.XMLTYPE; 
    BEGIN 
     sys.utl_dbws.set_http_proxy('Host name : Port'); 
      service_qname := sys.utl_dbws.to_qname('ns1', 'process'); 
       service_      := sys.utl_dbws.create_service(service_qname); 
       call_         := sys.utl_dbws.create_call(service_); 
        sys.utl_dbws.set_target_endpoint_address(call_, 'http:/host name : port/soa-infra/services/OFS/HelloWorld/helloworld_client_ep'); 
        sys.utl_dbws.set_property( call_, 'OPERATION_STYLE', 'process'); 
        request       := sys.XMLTYPE('<ns1:process xmlns:ns1="http://xmlns.oracle.com/OFSOrderServices/HelloWorld/HelloWorld"><ns1:input></ns1:input></ns1:process>'); 
     response      := sys.utl_dbws.invoke(call_, request); 
     return response.extract('//HelloWorld/child::text()', 'http://xmlns.oracle.com/OFSOrderServices/HelloWorld/HelloWorld').getstringval(); 
     DBMS_OUTPUT.PUT_LINE ('Values of OutputsVariables8');
--  Return 'S';
   END;
Execute----the below code:
  Select HelloWorld_WebServices('Hi') from dual;
Error:
ORA-29532: Java call terminated by uncaught Java exception: java.lang.NoClassDefFoundError
ORA-06512: at "SYS.UTL_DBWS", line 403
ORA-06512: at "SYS.UTL_DBWS", line 400
ORA-06512: at "APPS.HELLOWORLD_WEBSERVICES", line 74
29532. 00000 -  "Java call terminated by uncaught Java exception: %s"
*Cause:    A Java exception or error was signaled and could not be
           resolved by the Java code.
*Action:   Modify Java code, if this behavior is not intended.

Answer 1

Well, you should first test if your webservice is reachable with a simple WS - Client or a Browser - Plugin, then verify the respones of the web service and after that you can take further investigations on your problem domain. The error - message refers to a line in your function, obviously, but I can't see which line and because there is more than one call to sys.utl_dbws I don't see at what point the script fails. NULL - Pointer - Execptions usually indicate that a method was invoked on a variable which should contain an object reference but is NULL.