@Test
public void givenContextFilter_whenJavaObject_thanJsonCorrect() {
    ContextValueFilter valueFilter = new ContextValueFilter() {
        public Object process(BeanContext context, Object object, String name, Object value) {
            if (name.equals("DATE OF BIRTH")) {
                return "NOT TO DISCLOSE";
            }
            if (value.equals("John") || value.equals("Doe")) {
                return ((String) value).toUpperCase();
            } else {
                return null;
            }
        }
    };
    JSON.toJSONString(listOfPersons, valueFilter);
}