PartNumber          int                 // only useful in case of GetObject/HeadObject
	CheckPrecondFn      CheckPreconditionFn // only set during GetObject/HeadObject/CopyObjectPart preconditional valuation
	EvalMetadataFn      EvalMetadataFn      // only set for retention settings, meant to be used only when updating metadata in-place.

	TooBigDecodedLength
	BadSignature
	BadMD5
	MissingUploadID
)

// Wrapper for calling HeadObject API handler tests for both Erasure multiple disks and FS single drive setup.
func TestAPIHeadObjectHandler(t *testing.T) {
	ExecObjectLayerAPITest(ExecObjectLayerAPITestArgs{t: t, objAPITest: testAPIHeadObjectHandler, endpoints: []string{"HeadObject"}})
}

		case "PostPolicy":
			// Register PostPolicy handler.
			bucket.Methods(http.MethodPost).HeadersRegexp("Content-Type", "multipart/form-data*").HandlerFunc(api.PostPolicyBucketHandler)
		case "HeadObject":
			// Register HeadObject handler.
			bucket.Methods("Head").Path("/{object:.+}").HandlerFunc(api.HeadObjectHandler)
		case "GetObject":
			// Register GetObject handler.

				rinfo.ReplicationAction = rAction
				rinfo.ReplicationStatus = replication.Completed
			}
			return
		}
	} else {
		// SSEC objects will refuse HeadObject without the decryption key.
		// Ignore the error, since we know the object exists and versioning prevents overwriting existing versions.

// -----------
// The HEAD operation retrieves metadata from an object without returning the object itself.
func (api objectAPIHandlers) HeadObjectHandler(w http.ResponseWriter, r *http.Request) {
	ctx := newContext(r, w, "HeadObject")
	defer logger.AuditLog(ctx, w, r, mustGetClaimsFromToken(r))

	objectAPI := api.ObjectAPI()
	if objectAPI == nil {
		writeErrorResponseHeadersOnly(w, errorCodes.ToAPIErr(ErrServerNotInitialized))
		return

      ObjectOutputStream out = new ObjectOutputStream(bytes);
      out.writeObject(object);
      ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(bytes.toByteArray()));
      return (T) requireNonNull(in.readObject());
    } catch (IOException | ClassNotFoundException e) {
      throw new RuntimeException(e);
    }
  }

  private Platform() {}

        }

        try (ASN1InputStream stream = new ASN1InputStream(content)) {

            ASN1ObjectIdentifier kerberosOid = (ASN1ObjectIdentifier) stream.readObject();
            if (!kerberosOid.getId().equals(KerberosConstants.KERBEROS_OID)) {
                throw new PACDecodingException("Not a kerberos token");
            }

            int readLow = stream.read() & 0xff;

     * Empty token causes readObject() to return null, which leads to NullPointerException.
     */
    @Test
    void testConstructor_EmptyToken() {
        // 1. GIVEN
        byte[] emptyToken = new byte[0];
        Map<Integer, KerberosKey> keys = new HashMap<>();

        // 2. WHEN & 3. THEN
        // When ASN1InputStream.readObject() returns null due to empty input,

  @SuppressWarnings("unchecked") // reading field populated by writeObject
  @GwtIncompatible // java.io.ObjectInputStream
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    stream.defaultReadObject();
    keyTypeOrObjectUnderJ2cl = (Class<K>) requireNonNull(stream.readObject());
    /*
     * TODO: cpovirk - Pre-size the HashMap based on the number of enum values? (But *not* based on

   */
  @GwtIncompatible // java.io.ObjectInputStream
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    stream.defaultReadObject();
    @SuppressWarnings("unchecked") // reading data stored by writeObject
    Class<E> localType = (Class<E>) requireNonNull(stream.readObject());
    type = localType;
    enumConstants = type.getEnumConstants();