#vulnerable code 
                                public void testDeepPrefixedUnwrappingDeserialize() throws Exception
    {
        DeepPrefixUnwrap bean = mapper.readValue("{\"u.name\":\"Bubba\",\"u._x\":2,\"u._y\":3}",
                DeepPrefixUnwrap.class);
        assertNotNull(bean.unwrapped);
        assertNotNull(bean.unwrapped.location);
        assertEquals(2, bean.unwrapped.location.x);
        assertEquals(3, bean.unwrapped.location.y);
        assertEquals("Bubba", bean.unwrapped.name);
    } 
                            #location 5 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public void testDeepPrefixedUnwrappingDeserialize() throws Exception
    {
        DeepPrefixUnwrap bean = MAPPER.readValue("{\"u.name\":\"Bubba\",\"u._x\":2,\"u._y\":3}",
                DeepPrefixUnwrap.class);
        assertNotNull(bean.unwrapped);
        assertNotNull(bean.unwrapped.location);
        assertEquals(2, bean.unwrapped.location.x);
        assertEquals(3, bean.unwrapped.location.y);
        assertEquals("Bubba", bean.unwrapped.name);
    }