oracle调用webservice

oracle掉用webservice，提示ORA-29532: Java 调用被未捕获的 Java 异常错误终止: java.lang.IllegalAccessException: java.lang.NoClassDefFoundError,请高手指教代码如下
create or replace
Function Test(
Xmlstring Varchar2
)
    RETURN VARCHAR2
  AS
    l_service utl_dbws.SERVICE;
    l_call utl_dbws.call;
    l_result ANYDATA;
    l_wsdl_url       VARCHAR2(1024);
    l_service_name   VARCHAR2(200);
    l_operation_name VARCHAR2(200);
    L_Input_Params Utl_Dbws.Anydata_List;
    code varchar(50);
  Begin
    L_Wsdl_Url        := 'http://www.usoftchina.com/ws95/services/vendor?wsdl';
    L_Service_Name    := 'vendor';
    L_Operation_Name  := 'vendorinfo';
    l_service         := UTL_DBWS.create_service(wsdl_document_location=>URIFACTORY.getURI(l_wsdl_url),service_name=>l_service_name);
    L_Call            := Utl_Dbws.Create_Call(Service_Handle=>L_Service,Port_Name=>Null,Operation_Name=>L_Operation_Name);
    L_Input_Params(0) := Anydata.Convertvarchar2(Xmlstring);
    L_Result          := Utl_Dbws.Invoke(Call_Handle=>L_Call,Input_Params=>L_Input_Params); 
    UTL_DBWS.release_call (call_handle=>l_call);
    Utl_Dbws.Release_Service (Service_Handle=>L_Service);
   RETURN ANYDATA.AccessVarchar2(l_result);
  EXCEPTION
  When Others Then
   RETURN SUBSTR(sqlerrm,0,2000000000);
  END test;webserviceoracle