refs #492 Added a test case. Thanks to Erwan Letessier.

https://groups.google.com/d/msg/mybatis-user/dqHzZjyZ4zo/E50uPsCgAQAJ

Author: harawata

src/test/java/org/apache/ibatis/submitted/usesjava8/refcursor/CreateDB.sql

@@ -84,8 +84,13 @@ CREATE OR REPLACE FUNCTION mbtest.get_order_out_params(
   detail_count out integer,
   header_curs out refcursor
 ) AS $BODY$
+DECLARE
+  order_exists boolean;
 BEGIN
-  open header_curs for select * from mbtest.order_header where order_id = ORDER_NUMBER;
+  select order_id is not null into order_exists from mbtest.order_header where order_id = ORDER_NUMBER;
+  if order_exists then
+    open header_curs for select * from mbtest.order_header where order_id = ORDER_NUMBER;
+  end if;
   select count(*) into detail_count from mbtest.order_detail where order_id = ORDER_NUMBER;
 END;
 $BODY$

src/test/java/org/apache/ibatis/submitted/usesjava8/refcursor/RefCursorTest.java

@@ -146,4 +146,20 @@ List<Order> getResult() {
       assertEquals("Anonymous", handler.getResult().get(0).getCustomerName());
     }
   }
+
+  @Test
+  public void shouldNullResultSetNotCauseNpe() throws IOException {
+    try (SqlSession sqlSession = sqlSessionFactory.openSession()) {
+      OrdersMapper mapper = sqlSession.getMapper(OrdersMapper.class);
+      Map<String, Object> parameter = new HashMap<String, Object>();
+      parameter.put("orderId", 99);
+      mapper.getOrder3(parameter, new ResultHandler<Order>() {
+        @Override
+        public void handleResult(ResultContext<? extends Order> resultContext) {
+          // won't be used
+        }
+      });
+      assertEquals(Integer.valueOf(0), parameter.get("detailCount"));
+    }
+  }
 }