* Protobuf serialization does not distinguish between `[]` and `null`.
API fields previously capable of storing and returning either `[]` and `null` via JSON API requests (for example, the Endpoints `subsets` field)
can now store only `null` when created using the protobuf content-type or stored in etcd using protobuf serialization (the default in 1.6).

    // No equals and hashCode; see ForwardingObject for details.

    @Override
    public String toString() {
      synchronized (mutex) {
        return delegate.toString();
      }
    }

    // Serialization invokes writeObject only when it's private.
    // The SynchronizedObject subclasses don't need a writeObject method since
    // they don't contain any non-transient member variables, while the

    // No equals and hashCode; see ForwardingObject for details.

    @Override
    public String toString() {
      synchronized (mutex) {
        return delegate.toString();
      }
    }

    // Serialization invokes writeObject only when it's private.
    // The SynchronizedObject subclasses don't need a writeObject method since
    // they don't contain any non-transient member variables, while the

* Protobuf serialization does not distinguish between `[]` and `null`. ([#45294](https://github.com/kubernetes/kubernetes/pull/45294), [@liggitt](https://github.com/liggitt))

    public boolean isEmpty() {
      return MapMakerInternalMap.this.isEmpty();
    }

    @Override
    public void clear() {
      MapMakerInternalMap.this.clear();
    }
  }

  // Serialization Support

  private static final long serialVersionUID = 5;

  Object writeReplace() {
    return new SerializationProxy<>(
        entryHelper.keyStrength(),
        entryHelper.valueStrength(),

        return new WrappedSet(key, (Set<V>) collection);
      } else {
        return new WrappedCollection(key, collection, null);
      }
    }

    // can't use Serialization writeMultimap and populateMultimap methods since
    // there's no way to generate the empty backing map.

    /**
     * @serialData the factory and the backing map
     */
    @GwtIncompatible

import org.lastaflute.core.message.UserMessage;

/**
 * The keys for message.
 * @author FreeGen
 */
public class FessMessages extends FessLabels {

    /** The serial version UID for object serialization. (Default) */
    private static final long serialVersionUID = 1L;

    /** The key of the message:  */
    public static final String ERRORS_front_header = "{errors.front_header}";

    /** The key of the message:  */

import org.lastaflute.core.message.UserMessages;

/**
 * The keys for message.
 * @author FreeGen
 */
public class FessLabels extends UserMessages {

    /** The serial version UID for object serialization. (Default) */
    private static final long serialVersionUID = 1L;

    /** The key of the message: Realm */
    public static final String LABELS_AUTH_REALM = "{labels.authRealm}";

* Fix issue in reconstruct volume data when kubelet restarts ([#36616](https://github.com/kubernetes/kubernetes/pull/36616), [@jingxu97](https://github.com/jingxu97))
* Ensure proper serialization of updates and creates in federation test watcher ([#36613](https://github.com/kubernetes/kubernetes/pull/36613), [@mwielgus](https://github.com/mwielgus))

- Protobuf serialization of metav1.MicroTime timestamps (used in `Lease` and `Event` API objects) has been corrected to truncate to microsecond precision, to match the documented behavior and JSON/YAML serialization. Any existing persisted data is truncated to microsecond when read from etcd. ([#111936](https://github.com/kubernetes/kubernetes/pull/111936), [@h...