private PropertyDescriptor getPropertyDescriptor(HintContainer deepIndexHintContainer) {
        if (pd == null) {
            pd = ReflectionUtils.findPropertyDescriptor(clazz, fieldName, deepIndexHintContainer);
            if (pd == null) {
                MappingUtils.throwMappingException("Property: '" + fieldName + "' not found in Class: " + clazz);
            }
        }
        return pd;
    }
Cleans out the {@link PropertyDescriptor} cache; when suspecting that
our PropertyDescriptor has lost its references, we want it to be re-built
(instead of getting the same instance from the cache).
core/src/main/java/com/github/dozermapper/core/propertydescriptor/JavaBeanPropertyDescriptor.java