#vulnerable code 
                                public void testHierarchicConfigRoundTrip() throws Exception
    {
        ConfigAlternate input = new ConfigAlternate(123, "Joe", 42);
        String json = mapper.writeValueAsString(input);

        ConfigAlternate root = mapper.readValue(json, ConfigAlternate.class);
        assertEquals(123, root.id);
        assertNotNull(root.general);
        assertNotNull(root.general.names);
        assertNotNull(root.misc);
        assertEquals("Joe", root.general.names.name);
        assertEquals(42, root.misc.value);
    } 
                            #location 7 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public void testHierarchicConfigRoundTrip() throws Exception
    {
        ConfigAlternate input = new ConfigAlternate(123, "Joe", 42);
        String json = MAPPER.writeValueAsString(input);

        ConfigAlternate root = MAPPER.readValue(json, ConfigAlternate.class);
        assertEquals(123, root.id);
        assertNotNull(root.general);
        assertNotNull(root.general.names);
        assertNotNull(root.misc);
        assertEquals("Joe", root.general.names.name);
        assertEquals(42, root.misc.value);
    }