PROCEDURE CallWebService(
    obj   ORA_JAVA.JOBJECT,
    a0    VARCHAR2) IS
  BEGIN
    args := JNI.CREATE_ARG_LIST(1);
    JNI.ADD_STRING_ARG(args, a0);
    JNI.CALL_VOID_METHOD(FALSE, obj, 'soa/CallWebSvc', 'CallWebService', '(Ljava/lang/String;)V', args); 
  END;

declare
my_object ORA_JAVA.jOBJECT ;
begin
my_object := CALLWEBSVC.new() ;
CALLWEBSVC.CallWebService( my_object, 'xmlData' );
end;