private boolean isChange(final K key, final V value) {
        if (!objectMap.containsKey(key)) {
            return true;
        }
        final Pair<V, C> currentVc = objectMap.get(key);
        Objects.requireNonNull(currentVc);
        return !Objects.equals(value, currentVc.first);
    }
replaces objects in this Map completely with given objects
<br>
Same effect could be reached by calling removeAll() followed by add(newObjects),
but performance is better when calling replace() method instead
main/src/main/java/cgeo/geocaching/utils/AsynchronousMapWrapper.java